Yes. If you chose a plan through Thatch, Thatch makes the initial payment and, wherever possible, sets up autopay with your carrier at enrollment.
If you have a 'BYOP' plan and brought your own plan details to Thatch when you onboarded, then you are responsible for making your premium payments.
If you’re not sure which one you have, check the View details button on the enrollment plan in question in your Thatch dashboard. The pop out will tell you if the plan is either a Thatch pays or Member pays plan.