subscription problem

so i registered for this 30 day trial to see if i could fix my computer (It doesnt btw), so i need a new computer and wanted to cancel my subscription then i realized the 30 day free trial wasn’t free at all and feel a bit stupid. How can i cancel my subscription and delete my credit card information?

sorry about my english :stuck_out_tongue:

https://support.avast.com/article/24/ (Orders and Renewals)