I am making an app with a login page asking for the Username and Phone Number and Password and I want to connect the data with a spreadsheet, I want to get the data again when the user enters the app at any time after login and closing the app and also want to update the data if the user wanted to change the Username or the Password or Phone Number
I want to save the information of the users like Username and Phone number and Password and also if any of the information the user has entered is wrong it won't enter the app and tell him that he entered something wrong
(You should really consider hashing your users passwords (and possibly their phone number as well)) i cannot understand you.