I cannot find a way to activate CIS reverse charge. is any of the common issue that may face?

Thanks for reaching out, michalis-aristod. 

Allow me to share some insights regarding activating the CIS reverse charge in QuickBooks Online.
 

The option is only available for the QuickBooks Online UK version. Please use the CIS in QuickBooks Online for the steps on how to turn this feature on.

If you have any additional questions, please them below. I'll be sure to help your out.