Using Adobe Sign with blank pre filled fields

Hi there - in my company we use Adobe to put together statements of work/engagement letters to send to our clients for work we complete with them. We have a standard template we use which has open fields which we complete before sending. We now want to use Adobe Sign to ask our clients to sign these engagement letters. However when I follow the steps to sign and send a test email, clients are asked to fill in any empty fields. (There are some fields which don't always need completing) and I would just need to ask clients to complete the signature field. Is there a way I can ensure Adobe Sign only asks clients to complete the signature field and not any of the blank fields.

Thanks!