Sign in to thunkable account without email

I’m helping teach a bunch of kids in india about mobile app development. Would love to use thunkable, but not a lot of them have emails or access to them (as this is usually something parents like to control). Is there some way we can help them log in, through a special code etc. ? I know thunkable, similar to mit app inventor, used to have this, but it looks like that feature of no-email-sign-on has been removed.

Please recommend alternative / next steps. Thank you so much!