When you join IMDbPro, you'll need to select between the individual monthly, individual annual, or group plan monthly (for up to 5 members) membership payment plan to ensure you're charged the correct fee when your free trial ends. Billing is automatic when your free trial ends, when your account is still active. You can always switch your payment plan before the end of the free trial on the Membership settings page.
You can cancel your membership at anytime during the free trial period and your card won't be charged. You'll still have access to IMDbPro until the end of your trial.
Please note that a group plan membership for up to 5 members does not offer a free trial period. Learn more about a group plan at: https://pro.imdb.com/groupplan