Give external sheet user ability to "Submit" or "Notify" me

Give external sheet user ability to "Submit" or "Notify" me

I use external sheets to collect data from external customers.

I want to give them an in-sheet way to tell me that they are finished.

Ideally it would be something like a "Submit" button that could trigger a crm-side event/action that sends me an email OR updates a field in crm.

Looking for ideas you have.

Thank you!

Ken