How can I change the confirmation message shown after form submission?

The default confirmation message shown after form submission is "Your response has been recorded." To change this default message, open your Google Form, click on the Settings gear icon, select the Presentation tab, enter the message you want and click on Save.

How to customize the message?

When users submit a form, they get a confirmation message. You can update this default message to make it more meaningful for your respondents. For example, when the user submits their feedback, you can add a thank you note and inform when they can expect an update from you.