Login without the need of a sign up page?

so i just started appgyver yesterday and i want to make a login page that works withount the need of a sign up page on the app, whish means take the data from a pre made database on xano and using it to login, i hope you understand and thanks in advance.

I imagine something like premade accounts its possible, im currently working with firebase, where you can make demo accounts, but i dont know if its possible to create password for these accounts (maybe its possible with xano), so one way i can think this is possible, is by creating a separate admin app where you only sign up accounts
of course this can work out if you dont need many accounts because someone should create all the accounts first.
And then if you do this the only thing left is to create only a sign in page in your app.

hope this helps

i see that help a lot thank you.