In order to complete the "Donate" task in the quests, you need to help a member of your club with their help request in the chat page by clicking on the helping hand and send a help.
First, a member of your club needs to ask for help with Catering orders or Online Orders by clicking on the little helping hand next to each order. This will put on a help request in the chat page of your club like usual. After that you just need to click on the hand to donate them and voila, the quest task is progressing! Every help you send will be counted for 1 donation and you don't have to cook beforehand to help. Pretty easy, right?
Hope this helps!