As Sunit mentioned, this can be configured in the event properties.
If you want the microflow to be triggered when the field is not selected, or want different hotkeys, you need some js. You can use this widget for keyboard shortcuts, incl enter: https://marketplace.mendix.com/link/component/119985.
Hope this helps!
Hi Vignesh ,
In Mendix 9 it is possible to do that in the text box widget , there you have a possibility to configure ON ENTER KEY press action in the event tab of the widget .
By default it is not there in the text area widget.
Sunit Kumar Dubey