An account is optional in Sarı Durak; the single-player game works without one. You can delete your account and the information linked to it in the following ways.
Inside the game
Menu → My account → Delete my account immediately and permanently deletes your email address, password, usernames, cloud save, progress and your name in past season archives from the server.
If you can’t get into the game
Email info@o1hangar.com with the subject “Sarı Durak account deletion” and include your account’s email address and username.
If you don’t have an account
Your single-player save is stored only on your device. Delete it with Menu → Reset game, or by deleting the app.
More details
What is kept, and for how long, is described in the privacy policy.