1. In the form for which you want to turn on this option, click More form settings More options button > Settings.

  2. In the Options for responses section under Notification, check Send email receipt to respondents.

    Option to send email notification to form respondents in Microsoft Forms

Once your respondent has filled out your form, the option, Send me an email receipt of my responses, is now available to him or her.

Option to send yourself an email receipt of your responses in Microsoft Forms

After submitting responses, respondents will then receive a confirmation email, which includes a thank you message and link to view their responses.

Email confirmation message and link to responses in Microsoft Forms


Source: Microsoft