Invoice - Email 

From Transaction tab, go to ‘Invoices’ tab (bottom-center of the screen)

Click on invoice number link from a particular invoice

You can now view the invoice details

Select a invoice type that should be emailed

Click on 'Email Icon'

Change email address by clicking on ‘Change’ button(if required)

Click on 'Send' button (top right of bottom sheet)

When email send successfully click on ok button in model

File will be sent as attachment to that email address