Here are the steps on how to delete any message in Telegram.
Step 1: Go to the message that you want to delete and select the message by tapping and holding it.
Step 2: You will see a trash icon at the top of the app screen and tap on the icon.
Step 3: You can delete the message on your side as well as on the contact's side by selecting the "Also delete for contact" option. Finally, tap on the Delete option.