Open the Instagram app or go to https://www.instagram.com/
Log in to your account
Open your profile
Tap/click the menu (three lines)
Go to Settings and privacy
Tap/click Accounts Center
Tap/click Personal details
Tap/click Account ownership and control
Select Deactivation or deletion
Choose Delete account
Select a reason for deletion
Enter your password when prompted
Tap/click Continue
Tap/click Delete [username]
Confirm to permanently delete the account