This video shows you how to modify in game textures in Car Mechanic Simulator 2021. The vanilla game allows you to edit just the signs and banners but if you want to go even further this video is for you.
UABE (for editing and saving):https://www.mediafire.com/file/suqmvu...
Asset Studio (for viewing and extracting): https://www.mediafire.com/file/9ygv6m...
GIMP (Optional for image editing if you don't have a program): https://www.gimp.org/