Hello Ryanrobertspie,
Welcome to the Community page,
So you can add this information in custom from styles section
main cog wheel>custom form styles>content>where it has a message to customer you can in either of the bottom boxes you can add the terms and conditions in there then when you go to print preview on an invoice or estimate it will show up for you.
If the terms and conditions are pretty comprehensive you could add it as an attachment as a separate document or you can also do this from a recurring transaction.