You can turn any printable thing into a PDF on iOS.
- Open the thing you want to print (web page, email, photo)
- Tap the Share button.
- Press the Print button.
- Now, find the preview screen and pinch out (two fingers, moving away from each other) until the preview becomes full screen (on phone 6S or greater, you can 3D-touch to pop it out)
- Now, you’re looking at a PDF, which has its own share control – you can now do whatever you want with it – save it to iCloud drive, email it, whatever you want to do.