You can only delete an Instagram account if you have the login credentials for that account
Log in to the Instagram account you want to delete
Go to the account deletion page in a browser
Select a reason for deleting the account
Re-enter the password if prompted
Confirm the deletion
If you do not have access to the account, use Instagram’s account recovery options
If the account is impersonating you or violating rules, report it to Instagram
If you are trying to remove the account from your device, log out of it in the app settings
If the account is connected in Accounts Center, remove it from there if needed