I want to let them access their apple email to delete some emails to make space to receive more emails. They are temporarily using an android device until they can get another apple device.
They can use any internet browser (even on a non-Apple device) and log into www.icloud.com and go to the mail app there (or log into https://www.icloud.com/mail/ ).
If they have two-factor authentication turned on and don't have any Apple device, they will need to use a trusted phone number to get a verification code. See: Get a verification code and sign in with two-factor authentication - Apple Support
They can use any internet browser (even on a non-Apple device) and log into www.icloud.com and go to the mail app there (or log into https://www.icloud.com/mail/ ).
If they have two-factor authentication turned on and don't have any Apple device, they will need to use a trusted phone number to get a verification code. See: Get a verification code and sign in with two-factor authentication - Apple Support
Do NOT remove your Apple ID from the phone and then let them sign in using their Apple ID. That effectively locks you out of the phone and should they not remove their information, trying to recover control of your phone would be an arduous process.
how to allow a family member to use my apple device for a few hours for checking their email?
