@joek41 wrote: ... how do I create it for her? ...
Note that the "adding-new-user-names-or-email-addresses" support article posted above, which once contained both "Add User" and "Invite User" instructions, now contains only "Invite User" instructions. Oddly, you may or may not have the Invite option in My Account / Users. We once had it in my service area in South-Central PA, but it was removed long ago, leaving only the "Add User" option.
The Forum post "How to Add, Invite, and Manage Users" by Forum Administrator ComcastJessie at https://forums.xfinity.com/t5/Internet/ANSWERED-How-to-Add-Invite-and-Manage-Users-on-Your-Xfinity/t... contains both "Add User" and "Invite User" instructions
Finally, to use the UserID you create as an email address, just add @comcast.net to the end of it.
