Hi Julia,
F&B stands for Food & Beverage Cost. It is sent by the Venue (Hotel) when a planner sends an RFP.
F&B minimum comes into the picture when sometimes the hotels have a minimum charge cost for it. It means that they would not be interested in having the event at their facility unless the F&B cost is at least a certain amount.
Hope this helps.
Best,
Ankita Gupta