How do I change my credit card to renew subscription?

This is mighty frustrating, i want to renew my subscription but can’t find how/where to change my credit card details so the payment goes through.

Grateful for someone to explain in simple English!

Many thanks
Richard

Contact Sales: https://support.avast.com/en-us/contact/sales/
If you don’t have an order # use 00000000 then explain your problem.

https://support.avast.com/en-ww/article/Sale-Billing-FAQ/