EatTill is made by Quantum App Forge.
In the app: open ⋮ → Household & sync → Delete my account, and confirm.
Without the app: email eattill.support@quantumappforge.dev from the Google account you signed in with, with the subject "Delete my EatTill account". We'll delete it within 30 days.
What's deleted: your sign-in (name, email, user ID), your household membership and your backed-up data. A private household is deleted entirely. A shared household keeps its shared pantry, lists and recipes for the other members. Data on your phone stays until you uninstall the app.
What's kept: nothing. Deleted backup data is removed from Google Cloud Firestore at once and from Google's backups on their normal schedule.
See also the privacy policy.