Unfortunately, there’s no way to delete a Gmail account without a password, you have to log in to Gmail to do that. Here are the steps:
Step 1. Sign in to your Gmail account on Google.
Step 2. Click the grid icon in the upper right-hand corner and select “Account.”
Step 3. Under the “Account preferences” section click “Delete your account or services.”
Step 4. Select “Delete products.”
Step 5. Enter your password.
Option that can be used
Try third party tool that is prepared for this purpose:- Delete Gmail account without a password