Open Instagram and go to your profile
Tap the menu icon
Go to Settings and privacy
Tap Accounts Center
Tap Personal details
Tap Account ownership and control
Tap Deactivation or deletion
Select the account you want to block
Choose Deactivate account or Delete account
Follow the on-screen prompts to confirm
If you want to block another user, open their profile
Tap the three dots
Tap Block
Confirm the block