Each individual plan can hold up to seven days. If you'd like to create a meal plan that is longer than 7-days, simply create multiple weekly plans and then combine them into a Collection.
For example, say you wanted to design a 21-Day Program. You would create three 7-day meal plans and name them Week 1, Week 2, and Week 3. When your meal plans are complete, add the meal plans to a Collection then share that Collection with your client.