The NewForm function changes the Form control's mode to FormMode.New.
Use the SubmitForm function in the OnSelect property of a Button control to save any changes in a Form control to the data source.
You can use Navigate to create or update context variables of the new screen.
More information about Form function and Navigate:
If you want to send email to the person what you selected by your form's datacard, you can try the following workaround, I test as next:
Firstly, you should create a connection to Office 365 Outlook and add it as a data source within your PowerApps app firstly.
Then add one label,label3.text:DataCardValue2.Selected.Email , the submit formula - onSelect =SubmitForm(Form1);SubmitForm(Form1);Office365.SendEmail(Label3.Text,"Send email from PowerApps","Item: hello")
More information about office365send email():
Hope this could be helpful.