Make a choice of color and composition of the product on the WP website

Good evening, dear freelancers!

The task in the existing and launched site on CMS Wordpress is to add a variation selector (color / filling) to the product page with a drop-down list, make the output of products already ready, only change the categories.

We ask you to write approximate labor costs (terms, cost).
We will be glad to cooperate, thank you for your attention to the project.