This may be old news for some, but yesterday I learned iPhones have a scanner and can make .PDFs. I sure wish I had know about this Monday when I sent 10 .jpgs to China. I could have done all that in 2 .PDFs.
Anyway, open Notes, open a new or an existing Note, and hit the camera icon. Scanner has been an option there since iOS11.
Here’s the article/details - Working from home and need a scanner? There’s a free one built into your iPhone.
So, prior to reading this thread, did you know that iPhones had a scanner?