Food delivery is the service. There must be a spot that this information needs to be entered. Are you in the review section? It will usually take you right where you need to make the entry. You may also need to enter the 6-digit code.
See page C-17 Codes
Check the instructions for schedule C, in the book is a table called "Principal Business or Professional
Activity Codes". Find a code that most closely matches your business. From your user name I'm going to assume you deal with baked goods, and your question appears to refer to Food Delivery. If you are a bakery then there is a section for Retail "Food & Beverage Stores" - which I think you fall into 445290 "Other Specialty Food Stores". If you business is delivery you might fit under "Other Services" 812990 "All Other Personal Services".
Review the lists to find a category that better fits your understanding of your business.
Accommodation, Food Services, & Drinking Places Accommodation
721310 Rooming & boarding houses, dormitories, & workers' camps
721210 RV (recreational vehicle) parks & recreational camps
721100 Traveler accommodation (including hotels, motels, & bed & breakfast inns) Food Services & Drinking Places
722514 Cafeterias & buffets
722410 Drinking places (alcoholic beverages)
722511 Full-service restaurants
722513 Limited-service restaurants
722515 Snack & non-alcoholic beverage bars
722300 Special food services (including food service contractors & caterers)