Gst registration requirement

A small fast food shop/restaurant without sitting or with sitting wishes to attach his business with Zomato/swiggy, is he required to register in gst , as his turnover is less than 20 lakhs

Will Zomato pay tax under tcs provision or on behalf of restaurant or not. if yes, whether ITC be available to shop keeper

the Zomato charge some amount for its service like 30%, in this case also charge gst, will this ITC can be claimed by shopkeeper/restaurant

kindly clarify above three points