To delete your MuseScore account, please follow these steps:
I subscribed through the MuseScore.com website:
Log into your account on our website.
Go to Account Settings or click your profile icon (located at the top right corner) and choose 'Settings' in the dropdown.
Click the 'Account' tab, scroll down, and select 'Delete account'.
Confirm by clicking the 'Delete account' button.
You will receive a notification 'Your account has been successfully deleted!'
I subscribed through the MuseScore mobile and tablet app:
Open MuseScore mobile app.
Go to the 'Profile' section and log into your account.
Click on the options icon (three horizontal dots at the top of the screen).
Select 'More', then select the 'Delete account' button.
Confirm by clicking the 'Delete account' button.
You will receive a notification 'Your account has been successfully deleted!'