PDF Merge

How to merge PDF files

We’ll show you how to merge few PDF files into a single one.

Using an online application has a few advantages over installed software. 

  • safer to use: installing software always carries the risk of infecting your computer with a virus
  • most likely works on a mobiles/tablets as well
  • you can use it with older or lighter computers, don’t need a powerful CPU or tons of memory
  • always up to date with latest bug fixes and features

How to merge PDF files online

The basic scenario is very simple:

  1. Open the PDF Merge webpage in your browser
  2. Drag and drop your files onto the webpage
  3. Click Merge PDF then Download your result.

That’s it. Super simple!


How to merge PDFs and create a table of contents?

Generating a table of contents is handy for navigating a merged PDF. 

The first page in the merged document will contain a list of all chapters, with clickable links to navigate directly to the first page of each. The starting page number is also displayed.


To create a table of contents, click More options and then update the Table of contents option to generate the TOC based on either filenames or document titles.

How to combine PDFs and put filename in footer of each page

It’s handy to know the source of each merged PDF page. This is easy when the filename or document name is stamped in the page footer, for each merged page.

To do this with Sejda’s Merge PDF tool, click More options and select Add filename to page footer.


How to combine PDF forms that use the same form field names

Let’s say you often get multiple forms emailed to you, same form but with different content.

When you try to combine the files with Acrobat you receive an error message saying that you can’t merge the forms because the field names are the same. It suggests using a “portfolio” as a workaround, otherwise all the fields with the same name get the same value.

There’s 4 options to handle this with Sejda PDF’s merge tool.


First option is to Discard all form fields metadata. The widgets will remain rendered on the pages, together with the filled in values. The downside to this option is that you can’t extract pairs of field names and values anymore. The field metadata is gone.

Next options are to Merge the forms into a single form. This won’t handle duplicate form field names: all the fields with the same name get the same value. 

There is however a Merge the forms renaming duplicate fields which will handle duplicate form field names: each field with a duplicate name gets a new name that is unique across the document.

The last option is to Flatten the form fields which means the input becomes read-only, the value is preserved but it cannot be changed anymore. (It’s also not a form field anymore).

Give each option a try and see which one works best for you.