If you are using a form control, the form has a onSubmit property that you can use to navigate to a new screen or to show a pop up or a modal with the success message.
However, If you are using a patch function instead of Submit(Form) formula then you can check if there were any errors from the patch(). If there weren't any errors you can navigate to a new screen or show a pop up or a modal with the success message.
Patch(DataSource, Record); If(IsEmpty(Errors(IceCream, EditRecord)), <Show Success Message>, <Show failure message>)
You can find a similar scenario as yours on the page.