If a user is taking advantage of a free trial or adds a new payment method to their wallet in My Account, they might see a small verification/authorization charge on their credit card or PayPal statement.
The reason the user sees an authorization on their statement is, that in order to verify the user's credit card/PayPal account entered during the checkout process or when they add a new payment method in My Account, we make a small verification/authorization charge ($1 converted into the local currency) to the user's payment method to ensure, that the card/PayPal account is valid and ready to be charged once the free trial converts into a paid subscription or the subscription is due to be renewed with the new payment method.
There is no actual charge made to the user's credit or debit card or PayPal account, it's just an authorization, that is voided right after the card/account is verified.
A similar behaviour might occur if 3DS SCA is enabled. In case of trials and promo codes, we will be initiating the transaction with the whole amount (of the full subscription price), receiving 3DS authorization for the whole amount, and then settling the actual lower amount by making a partial capture or in case of free trials reversing the full amount of the charge altogether.
More information about this is available here.