To be eligible for the friends and family rate, you will need a signed form from the manager of a Marriott location for each property at which you will be using the rate.
For example, the sales manager at a property I've used regularly for over 2 years was able to secure 3 forms, signed by the front desk manager of that property, for use at 3 alternate Marriott properties of my choice.
__________________ Dodge DeBoulet - No Longer The Crunchy Other White Meat ByProduct
Programs: SPG Plat, HH Diamond, PC Plat Amb, BMI *G
These have been posted before, so I'm only repeating what has been published.
MMF is the friends and family code. As has been said, you will need a form to be authorised by someone at property or a central office basis. I've used these a few times and have always been asked for it when checking in. I'm sure your contact will sort you out.
Happy honeymoon planning. Where are you thinking of if you don't mind me asking?