The anticipation period corresponds to the number of days of preparation needed to plan your service.
For example, if you set an anticipation period of 3 days, this means the client will need to book you at least 3 days before their event. Less than 3 days before their event, your offerings won't be visible to them.
This period protects you from last-minute orders you wouldn't be able to fulfill. It's up to you to set it based on your general terms and conditions.