דרושים פרילנסרים לפרויקט קטן של TRACKING באתרי וורדפרס

we have 2 wordpress websites with links on them to another website

We have a new affiliate pointing to those websites.
The affiliate send some data (query params) that we need to catch, save in a cookie and move forward with every link to a different website

The idea is to replace data on the link with cookie data( if the cookie has data ).
The solution need to be php code cause all the links are in separated php files on the 2 websites