How do you make login system spreadsheet?

I already knoe how to implement login and SignUp system but i don't know how to get specific user data in the user's id, I just need an IDEA

I need an idea that how i can implement login and SignUp system but with specific user details in the labels after login.
As we know the firebase is good for that work but at the end it is not free, I want to implement it by Google Spreadsheet All user data but show the specified user data by imei or any id.

Where will these specific user details come from?
It is now not possible to use/access the IMEI code.
You can generate a unique ID in the spreadsheet when the user is created
The user can add details on registration

Show what you expect your user details to look like, then we can help from there.

This is not by any means the canonical on register/login, but may help:

I want to show user details on the user's any screen on labels, How many sheets does a spreadsheet handle (or number of sheets can be in one spreadsheet)

  1. There is no limit to the number of sheets you can have in a spreadsheet, just the number of cells/file size.

  2. Seems like overkill to store data this way, when you can store it all in one record on one sheet?

I want to create thousands of the sheets by script, every sheet have unique name, And user only able to access the sheet when the
imei = sheetName.
Is it possible because i don't want any crash in my app and delay also.

Check google sheet limitations to understand what you can do.

1000's of girds/tabs/sheets in a spreadsheet won't be very manageable, or very quick. This may also present quota issues if run off a single account.

See here about IMEI

So can you suggest me any method that is permanently free as like google spreadsheet. I can do this with my firebase but i am not able to purchase it's premium plan.

It is difficult to advise without having a better understanding of your data storage requirements and the scope of your project.

As you probably know:

If you have to pay something for your data needs, then you may need a business model with your users (one time payment/subscription/ or god forbid Ads) to recover costs