I do not want to send a invoice by email but it wont let me save without adding email address please help?

It’s nice to see you in the Community, @nbyford.

Make sure that the customer’s preferred delivery method is set to None and the Send later box on the invoice isn’t marked, so you can save the transaction successfully (See screenshot).

To verify the first scenario, follow the steps below:

1. Go to the Sales menu and select Customers.
2. Click the name of the customer.
3. Under the Customer Details tab, click Edit.
4. On the Customer information window, click the Payment and billing tab.
5. Choose None in the Delivery Method drop-down.
6. Hit Save.

Here's an article for reference: How to edit customer information.

That should get you pointed in the right direction.

Keep me updated on how this goes, and if you need anything else. Have a great day!