The first step to permanently deleting your account is to log into your account. Without account access, it will be nearly impossible to delete your account without getting help from Twitter customer service reps.
After you have accessed your account, you can go ahead and access your user settings. On a desktop, this is a small button on your sidebar that is represented by three dots.
Once you click on Settings and Privacy, a new page should open up. On this page is a menu with a few breakout options. Click on the menu option that reads Your Account. On a desktop, this option is at the center of the screen.
Once you click that menu button, a secondary page will open up. This page details everything that will happen once you deactivate your account. Once you’ve read through the details, you can go ahead and click Deactivate.