There is no single-click button to leave or delete a free registered developer account on the Apple Developerwebsite. Because it is a free account (just an Apple Account registered with the developer agreement), you can simply stop using it, or opt out of developer notifications and beta software updates.
Steps to Stop Using and Clear a Free Developer Account
- Turn off Developer Betas: On your Mac, go to System Settings > General > Software Update, click the Info (i) button next to Beta Updates, and turn it Off.
- Stop Developer Emails: Sign in to your account preferences on the Apple Developer portal and uncheck email preferences, or ignore future developer mailings.
- Request Account Closure: If you want your profile completely wiped from Apple’s developer database, you must submit a request directly through Apple Developer Support by choosing Membership and Account.