The login screen on Instagram will require a user to sign in to access the site. After entering their username and password, they'll be taken to the account's homepage. After this, they'll be taken to the account page. Once they've logged in, the account will automatically be linked to their email address. If they're not, they'll be able to see it. Then, they'll be able to change their account's contact information through settings.

See also - https://thedigitaltechnology.com/login-guide-for-instagram-from-device/