Instructions for registering a business in Philadelphia, including how to choose your business structure and get a City tax account number. Enter your business address.Do not use a Post Office Box number as your business address. Learn about forming and registering your business online, and how to complete other types of business filings. Register your business (opens in a new tab). Use a Business Bill of Sale to set out the terms for the sale of a business and transfer the ownership and all assets to the buyer. Legal advise and agreements for purchasing a business or selling a business. Get our free, updated 2022 checklist for business buyers. Find information about the types of business filings and registrations you need. Purposes of completing Pennsylvania Certificate of Title applications (buying or selling) on behalf of a business organization or a non- profit corporation.