If the Seller is not offering Buyer Owns Rights, where you'd keep all IP in the delivered work, and is not offering an Unlimited license, you will need to message the Seller to negotiate a custom license for your purposes.
The reason HostJane requires a licensing system is to ensure that Work done on our platform has clear legal ownership and legal uses.
Our goal is to run a platform that is fair to both the Seller doing the Work and the Buyer commissioning or buying the Seller's End Product.