I use a couple of apps called Evernote, Scanable and Sortly.
Evernote is the main one. I use it to keep my recipe book, meal plans, links to pdf's of instruction manuals, scanned copies of important documents, scanned copies of things like insurance details, bills, lists (shopping lists, lists of my OH and DD's shoe and clothing sizes, cat vaccination details and microchip numbers, house maintenance lists and all sorts of other things), holiday planning (links to websites of places we want to visit, information such as supermarket locations, flight details and accommodation details with things like keysafe codes). I share some of those lists with my OH, so when he is out at lunchtime he can see if there is anything he can do. Evernote also has a web clipper, where I can clip pages, recipes etc from the web. I have an Evernote notebook set up as an 'Inbox' where those things go, so that I can then sort them in to their proper place.
Scannable is an app that you can use to scan and digitise documents. It creates searchable content, so if you scan a phone bill, it will create tags so that you can search for it. You can set it up to send things directly to Evernote (mine goes to my 'Inbox'), and you can still search for the tags in Evernote.
Sortly is great if you are moving house, or if you want to keep an inventory of belongings for insurance. If you are moving house you can use it to list the items in a box, and then print a label with a QR code to stick on your box. We have recently done two moves (one international) in six months, so it was invaluable to me!