Thank you for posting, @Majestic_Cadencef7c2.
I understand how alarming it can be to expect a free trial and then see charges appear on your account shortly afterward.
For subscriptions purchased through Apple, the trial begins immediately, and Apple may place an authorization or charge on your payment method when the subscription is started.
Since your Acrobat Premium subscription was purchased through Apple, you'll need to manage the subscription through your Apple account. You can find Apple's instructions for viewing and canceling subscriptions here:
https://support.apple.com/en-us/118428
If you no longer want the subscription, you'll want to cancel it as soon as possible. Based on Apple's subscription terms, you may be eligible for a refund if you cancel within the applicable cancellation period.
Because the purchase was made through Apple, any refund eligibility or billing questions should be reviewed by Apple.
Please update this discussion if you have any additional questions, @Majestic_Cadencef7c2.