How can I add terms and conditions to a quote or invoice?

If your terms are brief, add them to the footer text of the quote/invoice:

1. Go to My account, then select Settings.
2. Under the Sales section, click Invoice design.
3. Click ️🖉edit next to Invoice payment & bank footer text. - IDK
   
4. Click Sales terms sets for customers. - IDK
   
5. Or just edit it directly. - IDK
   
6. Click Save.

If your terms span a full page or more, set it as a supplementary PDF attachment:

1. Go to My account, then select Settings.
2. Under the Email templates section, click Quote or Tax invoice.
3. At the bottom-right, click Upload a PDF file to upload your terms as a supplementary PDF attachment.