To add an Acceptance block to your proposal, click the + icon located at the bottom of any block and click 'Acceptance'

This will add an Acceptance section to your proposal. You can only have one per proposal, so if you added one already, then you'll see a message to let you know that you can't add another one without removing the other.

Don't worry if you need multiple people to sign the proposal, you still only need to add one block at this stage, you'll add your signers later.

You'll notice that the {{first_name}} and {{surname}} merge tags are in the acceptance text by default. You don't need to do anything with these as they will be automatically replaced with your client's name when they open the proposal.
Bear in mind you also won't see these replaced on the proposal preview, because it's not tied to a specific recipient.

To read more about how you can customize the acceptance block, click here