Where is the delete link located?

You have to place it manually on the front end, or use it via the edit profile page in the admin. Also, the delete button is not available for administrators because they should not be able to delete their own accounts (helps to avoid losing admin access). Therefore, if you’re logged in as an administrator, you won’t see it.

Excuse me. How do you manually place the button in the frontend? Is there any shortcode?

Here’s the shortcode for displaying the delete-account button (including accepted arguments):

[wp_delete_user_accounts label="" button_text="This will cause your account to be permanently deleted. You will not be able to recover your account."]