Setting up an Apple ID for my elderly mom

Clear your stuff off:

What to do before you sell, give away, or trade in your iPhone or iPad - Apple Support

then set it up “for yourself” as a “new” device, and not restoring any existing backups, and creating a new Apple ID:

Set up your iPhone or iPad - Apple Support

Setup basics - Apple Support

When creating the new Apple ID, set up a recovery contact and consider a legacy contact:

Set up an account recovery contact - Apple Support

How to add a Legacy Contact for your Apple ID - Apple Support

Set up Family Sharing:

Set up Family Sharing - Apple Support

Seriously consider setting up iCloud backups, too:

How to back up your iPhone or iPad with iCloud - Apple Support

Ans then later on… Here is the user’s guide:

iPhone User Guide - Apple Support

If this follows the usual patterns I’m encountering around here, problems tend to be forgotten passcodes and passwords, and a few obscure settings “surprisingly” and “unexpectedly” reconfigured, among ongoing issues. If you have a protective case for the iPhone, a slip of paper with the passwords and passcodes can go underneath.

Simply create an eMail and an AppleID for her; then setup a phone for her.