A free program for Android, by Bostan Constantin.

This application can be used to merge multiple PDF documents into one.

There are two ways to do this:

The first way is to use a custom popup file picker.

The second way is to use a native one, to select which PDF to merge from the device.

In order to do this, you need to make sure that you have all the background apps closed.

There are two ways to select PDF files: a custom popup file picker and a native one.

If you have a weak device, don't select too many files, the app may crash because of low RAM memory.