If you don’t have all the items or dishes you need for a delivery then you can ask for assistance to fill one of the crates per Delivery Truck. Simply tap on a crate and then you can either select “Load” if you have all the required items or “Ask For Help” if you need help. A request will go out to your friends, alliance members, and other Tasty Town players to donate the required item or dishes.
Once you have received help from another player you will be notified that a crate is ready to load.  The player's avatar will appear on the crate that they have helped you with and when you tap to accept the donation a Horse Shoe will be sent to the player.
You can also help other players load crates on their Delivery Trucks and as well as receiving a Horse Shoe, you will also receive Gold and XP when you donate items or dishes. To do so, click on your friends icon and then select the tab with the exclamation point icon (!). There you will find a list of your friends that have active help requests. Simply click on one and you will be automatically directed to the request, whether it's the delivery truck or the chillout area (if unlocked).