You can merge PDF files as needed but you can only use two PDF files one time. If you think its too much trouble to open two PDFs to read constantly, you can merge them into a new file to read and edit. After merged, a new PDF file will be created without affecting the pervious PDF files.
Here’s the steps of how to merge PDF files
- Select(long press/select icon) two PDF files you want to merge to get into the selected mode
- Tap the ‘Merge’ icon at the top-right of PDFs window to create the merged file directly
- The page order of the merged file will be in the order of the two PDF selections