Deactivating your account begins the process of deletion, but it doesn’t immediately delete your account. Instead, it gives you 30 days to consider your choice and change your mind. If you take no further action, though, your account will be deleted at the end of that 30-day window.
If you have subscriptions that you pay for through Twitter, those will need to be canceled on the platform where you registered for them.
Source: https://www.distractify.com/p/how-do-i-delete-my-twitter-account