I know absolutely nothing about this myself, but you may find something useful in these threads:
Can I open my own business?: forumosa.com/taiwan/viewtop … 88&t=40895
Food vendor permit: Food vendor permit
Advice for a small movable food store on the street: Advice for small movable food store on the street
How do I get a stall in a night market: forumosa.com/taiwan/viewtopi … 88&t=16032
Night Market Stand Startup Questions: forumosa.com/taiwan/viewtop … &p=1229934
Cost to do a night market stand/business: forumosa.com/taiwan/viewtop … 88&t=77497
Can a Foreigner Sell Things in a Night Market: forumosa.com/taiwan/viewtopi … 70&t=42303
How to start a restaurant/bar in Taiwan: How to start a Restaurant/Bar in Taiwan
opening a restaurant or cafe in Taipei: Opening a restaurant or cafe in taipei
Open a restaurant or food stand: what permits are required: Open restaurant or food stand. What permits, etc required