Simple CRUD web app for recording daily data/predictions, e.g. weight?

You can use a simple track open source app, for Android something like https://github.com/SamAmco/track-and-graph

I used Google Forms + Google Sheets to track electricity consumption. Every once in a while when I was coming back home, I stopped by the meter and entered its readings. Worth noting is that Google Forms did not handle decimals with a "number" field properly, at least not with comma separator.