You can remove a request on Instagram App by following these steps:
Go to your profile page on the app.
Tap on the three horizontal lines icon at the top right of your screen.
Tap on Settings.
Tap on Account.
Tap on Privacy.
Tap on Account privacy.
Scroll down to the Connections section and tap on Follow Requests.
Tap on the username of the person you want to cancel the follow the request.
Tap on Cancel Request.