You want a.pdf scanner app or photo scanner apps, which scans multiple documents and make them a .pdf file? I can tell you the second one. Camscanner is a really good app, which scans multiple photos and then convert then into single pdf file. It has both free and paid version. In the free version the app creates a very small watermark ‘ scanned by Camscanner’. That is not a issue for a regular user.
But as it looks a bit like a scan of your photo, it might be disturbing. I would suggest disabling watermark in the app settings. But how to remove the watermark or to make a new one on one of the photos? You might ask on Google and Bing what apps can remove image watermark from photo? You might search on Wikipedia, and it will give you all the relevant information and links. Also, google for Cam scanner and its review. Then you must read all the negative feedback and review of Cam scanner. But why watermark is better than other apps? You ask, the apps listed below are good, but they have not a watermark, and they could not remove watermark even in a photo and save your photo. You also may ask when can you get the same watermark removed? Furthermore, you can read my review and I have also posted a.