How can I make a screen that shows the user’s email and password that they used to sign in?
Use stored variable.
See this
I already built a functional sign in screen, but when I try to go onto another screen and display the email/password that was used to sign in, it shows up as undefined.
Follow the YouTube video to see how to do that.
You’ll need to show screenshots of your blocks or provide a link to your project. Without seeing how you have things set up, we can’t figure out what to fix.