Please note this is a paid plugin and you will need to subscribe to it or purchase a lifetime licence to use it.
The Freelancer Marketplace template has the Stripe Connect - Marketplace plugin pre-installed. However, you will need to navigate to the 'Plugins' tab of your editor and buy a license or subscribe to it.
Bubble plugin subscriptions are pro-rated. This means you can try the plugin out and if you un-install it after a few hours it will cost less than 10 cents!
Useful links for Stripe Connect - Marketplace plugin