Stanley,
Have a look at this documentation page
Not directly on the enter key, but this might give you some ideas on how to resolve your requirement.
Hi Stanley,
There is a widget in the appstore to be able to execute a microflow when you click on the enter key.
https://appstore.home.mendix.com/link/app/2674/Finaps/Textbox-enterkey-widget
Kind regards,
Wouter