A job application often involves four or five documents: a cover letter, a resume or CV, scanned certificates and a list of references. Whether they belong in one file depends on the employer. This guide covers how to decide, how to build a clean packet, and what limits published job portals set. For the mechanics of merging itself, see how to merge PDFs without uploading them and how to combine PDFs on Windows, Mac and phone. Those are not repeated here.
First check whether one file is wanted
Many portals have a separate slot for each document type. The USA Staffing help page says an applicant can add several documents under one document type by choosing additional documents in a drop-down list. The USAJOBS help page tells applicants to attach only the documents the announcement asks for. The UK Home Office careers page says to follow the specific instructions on the job advert, such as required formats and word counts. If a portal gives separate slots, merging everything into one file can make a reviewer's job harder.
Some systems do not take files at all. Government of Canada's GC Jobs guidance tells applicants to create a very simple, unformatted resume with no bullets, underlines or bold, and notes that the system removes most formatting on pasting. A packet PDF does not help there.
A single combined PDF fits best when the instructions say "one PDF", when applying by email, or when the form has one upload field.
Limits confirmed on official pages
At the time of writing (October 2026), the following were stated by the portal operators. Limits change, so check the portal's own help page before uploading.
- USAJOBS. Accepted formats are GIF, JPG, JPEG, PNG, RTF, PDF, TXT and Word (.doc or .docx). All documents must be less than 5 MB, and encrypted files cannot be uploaded.
- USA Staffing (the application system used by many US federal agencies). Documents must be under 5 MB, files cannot be password-protected, and the page names GIF, JPG, JPEG, PNG, RTF, PDF and Word. If a file meets the requirements but will not upload, check that its name has no special characters or blank spaces. It also warns that scanners may default to large PDFs that often exceed size limits.
- A US state HR portal (Tennessee). Each file must be under 8 MB. The help page suggests splitting a large document into smaller attachments, using the lowest resolution for pictures, giving each attachment a different name, and notes a file name limit of 24 characters.
- UK Home Office careers. No size limit is given on the page read, but it says not to include your name on any files you upload. Some UK recruitment is name-blind, so a file name that carries a name can matter.
UK Civil Service Jobs and APSjobs in Australia were checked too, but their help pages could not be read, so no limits are given for them here. If a portal gives no limit, keep the packet small enough for email, which is a safe habit rather than a rule.
A sensible order
No official page read for this guide sets an order. The career guide of San Jose State University, for example, says only to follow the employer's instructions and to name files clearly. The order below is common practice for one file, and the advert overrides it.
- Cover letter, one page.
- Resume or CV.
- Certificates and transcripts, most relevant first.
- References, if the advert asks for them in the same file.
Keep the packet as short as the advert allows. A reviewer scrolling through twelve pages of certificates is less likely to find the one that matters.
Build the packet: preparation
- Create the resume and cover letter as PDFs straight from Word or Google Docs. The SJSU guide says to save directly from those programs and warns that design-heavy templates are not always read reliably by applicant tracking systems. Text should stay selectable.
- Scan certificates flat and upright. Scanners often default to large files. USA Staffing suggests saving as JPG at a lower quality setting, for example 50 percent, when a file is too large.
- Fix the page orientation of every scanned page before merging. Rotate PDF has Rotate left, Rotate right and Rotate 180° buttons, and Save rotated PDF saves the result.
- Make page sizes consistent. A resume on A4 and certificates on US Letter will produce mixed pages. DocPro does not resize pages when merging, so if you need one size, use Resize PDF first, as in resize a PDF to A4. Photos of certificates added to Merge PDFs become one A4 page each with a 10 mm margin.
- Name files clearly before merging, for example FirstName-LastName-Resume.pdf, which is the form the SJSU guide suggests. Avoid special characters and spaces, since USA Staffing lists them as a cause of failed uploads.
Build the packet with DocPro
- Open Merge PDFs. Under Drop PDFs or images here, choose the cover letter, the resume and the certificates. Photos of certificates are accepted as well as PDFs.
- Put the files in order with the up and down buttons on each row. The merged file follows the list from top to bottom.
- Press Merge PDFs, then download the result. It is saved as merged.pdf. Rename it, for example FirstName-LastName-Application.pdf.
- If the page count or order is wrong, open Organize pages, drag pages into place or delete extras, and press Save new PDF.
- To add numbers, open Add page numbers. Choose a Position and a Format such as Page 1 of 10, set Start at, tick Skip the first page (cover) if the cover letter should not carry a number, and press Add page numbers.
- Check the file size against the portal's limit. If it is too big, use Compress PDF, as described next.
Reducing size without damaging the resume
DocPro's Compress PDF re-renders every page as a picture at a chosen Quality (High quality, Balanced, Small or Smallest), and it can aim for a Target size (KB). Text on those pages is no longer selectable afterwards. For a job application that matters, because a portal that reads the resume as text then sees nothing.
The safer order is to compress the scanned certificates on their own, then merge the compressed certificates with the original resume and cover letter. That way only the scans, which are pictures already, become pictures again. The task pages for merging and compressing and for scanning to PDF show the sizes involved.
Do not add a password to the packet. USAJOBS and USA Staffing both reject encrypted or password-protected files.
Bookmarks and navigation
A long PDF is easier to read with bookmarks or a table of contents. DocPro's Merge PDFs does not create bookmarks or a contents page. Page numbers are available through Add page numbers. If the advert allows only a few pages, skip these extras and keep the packet short.
Check the final file
- Open it in a second viewer, such as another browser, and scroll every page.
- Check the page count, the order and that nothing is upside down.
- Try selecting text on the resume page. If you cannot, the resume has been turned into a picture.
- Check the file size and name against the portal's rules.
- Check that no personal details are present that the advert asks you to leave out, such as a name on every page for name-blind recruitment.
What DocPro cannot do here
- It cannot check an application against a portal's rules. Limits are the portal's to set.
- It does not create bookmarks, and it does not resize pages as part of Merge PDFs.
- It cannot read scanned pages as text for applicant systems. If a certificate is only a picture, a portal cannot search it. For a scanned page you need to search, OCR PDF can add a text layer.
- It cannot decide what an employer wants. When the advert says separate files, upload separate files.
Frequently asked questions
Should the cover letter and resume be in the same PDF?
Only if the employer asks for one file or the portal has a single upload field. If the portal has separate slots, upload them separately as the USAJOBS help page advises: attach the documents the announcement asks for.
What file size limit do job portals use?
USAJOBS and USA Staffing say documents must be under 5 MB. A Tennessee state HR portal says each file must be under 8 MB. Other employers differ, so read the portal's help page.
Can I password-protect my application PDF?
No, not for USAJOBS or USA Staffing, which say encrypted and password-protected files cannot be uploaded. Leave the file unprotected.
Will compressing the packet make my resume unreadable to the system?
It can. DocPro's Compress PDF turns pages into pictures, so the text is no longer selectable. Compress the scanned certificates alone, then merge them with the original resume.
Does DocPro upload my documents?
No. Merge PDFs and the other tools used here run in your browser and the files stay on your device.