When it comes to seller onboarding at a marketplace, the first step is to have the seller register an account on the platform. This may involve providing personal and business information, such as legal name, address, tax ID number, and banking information. During the seller onboarding process, the marketplace platform may also verify the seller's identity and conduct background checks to ensure that they are a legitimate business. Once the seller onboarding process is complete, the seller will typically be able to list their products on the marketplace and begin accepting orders from customers.