StepTap the three-dot menu at the top and hit Select. In the list of files, you can add more by tapping the plus sign. Drag and drop PDFs to merge them into one file with our PDF combiner. The easiest way to combine two or more PDFs into a single file is by using the Files app. Merge PDFs. Open the Files app on your iPhone. In Adobe Acrobat. Select Missing: iphone Open a document that you would like to merge with another one (s)Tapin the top right corner and select Insert FileSelect the documen