CBLHandyman Afternoon!
You may need to switch to ‘Classic’ invoicing in order to achieve this, but it is possible.
Assuming you have your clients email address added to your account and you sent the invoice to them via Crunch.
Go to Sales > Invoices, make sure the toggle at the top is on Classic.
Use the ‘Options’ menu on the relevant invoice, and choose ‘Record Client Payment’.
You should then see a tick box called “Send confirmation email if settled”, which you can go ahead and check.
This should then send confirmation of the invoice being settled 😃