You can save a default email address to a vendor so that when you email the invoice, manifest, and/or QA results, the email address is auto-populated.
Click Print/Share and select Email Invoice from the drop-down:
Click the Vendor link to access the Vendor Details:
Enter a default address in the Email field, then click Save:
Add a second email address in the default field if the vendor usually wants you to send to two addresses:
Click on the Contacts tab, then +Add to enter more contact addresses you might need saved:
The additional email addresses will then be available to copy and paste when clicking the Vendor link while creating your email.