How to merge multiple PDFs into one on Android

Many portals give you a single upload box for "supporting documents", but you have five: an ID proof, an address proof, two certificates and a photo. The answer is to merge them into one PDF, in a sensible order, under the size limit. Here is how to do it neatly on an Android phone.

Step 1: Gather everything in one place

Documents arrive from everywhere: email attachments, chat downloads, camera photos, old scans. Before merging, collect them in one folder or app so you are not hunting while the portal times out. Check that each file is the latest version, and rename them so you can tell them apart, for example 1_id_proof.pdf, 2_address_proof.pdf, 3_marksheet.pdf.

Step 2: Turn photos into proper pages

If some documents are photos rather than PDFs, scan them again with a document scanner if you can, so they are flat, cropped and on a white background. A tilted photo of a certificate in the middle of a clean PDF looks careless, and a large photo can blow the size limit by itself. For ID cards, consider putting the front and back on a single page.

Step 3: Decide the order

If the form lists the documents in a particular order, follow it exactly. If not, a logical order helps whoever checks your application:

1. Identity proof
2. Address proof
3. Educational certificates, oldest to newest (or as asked)
4. Category, income or other certificates
5. Any declarations or additional documents

Step 4: Merge into one PDF

Android does not include a built-in "merge PDF" button in most phones' file managers, so you need an app or tool that can combine files. Whichever you use, the steps are similar:

1. Open the merge tool and select the files.
2. Arrange them in the order you decided, by dragging if the tool allows.
3. Merge, and give the new file a clear name such as supporting_documents.pdf.
4. Open the merged file and scroll through every page.

Step 5: Tidy up the result

• Remove extra pages, such as blank backs or duplicate pages.
• Add page numbers if the document is long; it helps reviewers and shows nothing is missing.
• Check rotation: every page should read the right way up.
• Check the size. Merging adds sizes together. If the result is over the limit, compress it. See how to compress a PDF to 100 KB.

Mixing photos and PDFs

A merged file often combines different kinds of pages: a scanned certificate, a phone photo of an ID card, a PDF downloaded from a website. Make them consistent before merging. Convert photos to PDF pages first, crop them to the edges of the document, and keep the orientation the same. If one source page is in colour and the rest are black and white, that is fine, but very large colour photos are usually what pushes a merged file over the limit, so resize those first.

Avoid uploading documents to random websites

Free online PDF mergers are convenient, but they require uploading your identity and financial documents to a server you know nothing about. Using a tool that works on your phone keeps your documents with you.

Merge PDFs on your phone with Stash-it!

Stash-it! is a free Android app that keeps your documents on your phone and includes 36+ tools for forms. Merge PDFs joins several files into one PDF, Pick pages keeps only the pages you need, Split a PDF breaks one apart, and Page numbers numbers every page. Both sides on one page puts the front and back of a card together, and Compress to a size brings the finished file under the limit. There is even a Portal-ready kit for getting your files ready for an online portal.

Open any document and tap Tools: the tools that fit it are shown first. Nothing is uploaded unless you share it. Tools use a few Stash coins, with 25 free every morning and the first use of every tool free. English and Hindi.

Before merging, you might need

• How to self-attest a document without a printer
• How to make passport-size photos at home
• How to resize a photo to 20 KB / 50 KB for online forms

Checklist

• The form expects a single combined file
• All documents present, latest versions, in the right order
• Every page upright, clear and not duplicated
• Within the size and page limits
• Named clearly so you upload the right file