Thanks for the replies.
I’ve read so many older forum posts from years ago…and bookmarked a ton…but when I want to find something, it seems I never can find what I’m looking for. And sometimes using AI, things can go around and around in circles.
I have an older relative who takes a couple of medications each day. She was keeping track of the times she took them on paper. Yes, they have the plastic pill holders by day, and even some apps out there that do this…but she said those apps were too confusing.
So, I sat down and built her an app the other day that handles everything for her. She can set her meds, times, amounts, how often, etc. It has an easy onboarding process for older people. Then it alerts her when it’s time to take a med…she clicks a button, and it logs it. If she misses one, it alerts her, etc. Too many features to mention…but all so simple to use.
Then she said she had a couple of friends who could use this also.
The whole app is built using code and using Bubble as a backend using JS Globs, but since her friends want to use it, I added the auth page using Bubble.
They create an account with their phone number and a 4-digit PIN. Thought that was easier for older people.
When they log in, they can click forgot pin and they get a text, blah, blah, blah.
So, I had remembered reading somewhere that signup/login should be in the backend, but I couldn’t find where I had read it.
Thank you for all the replies 
Added: When they create an account, they also get a text and can just click verify