I'm currently trying to figure out how to sync a 'Message' field over from Marketo to Dynamics CRM. We use a 'Contact Us' form on the website, and when filled out leads can input a message on why they are contacting us. This text populates a field under Lead Info called 'Message' and we want that field to sync over to CRM, but I went into admin to try and add the field to the sync, 'Message' isn't showing up as an option for the Field Sync. Is this something that needs to be created in Dynamics?
Yes, you should have created in Dynamics first and then mapped it in Marketo to have it created in Marketo.
If you have it created in Dynamics now, you may want to ask support if they can do the mapping for you.