There is an app called "Scanner Pro". It's $3.99 for a one time purchase.
Basically it lets you convert any physical document to a PDF or picture and also keeps a cloud-based storage for all the documents scanned. Not only that, but it has an automatic recognition system when scanning, so very rarely do you need any adjusting or cropping. It works faster than a printer scanner, lets you immediately email a scanned page, lets you do multiple pages in 1 PDF document, allows the user to create separate folders for handling documents and renaming, all in the app. It can be linked to iCloud so you have backups of everything, even if your phone blows up.
For example, I have folders for:
2017 taxes
2018 taxes
2017 rental property applications
Sheet music
Business cards
Government documents
I recommend it for any business owners, especially for tax purposes (the IRS accepts electronic receipts)
It's disgustingly useful.