Hey @It'sRatul by Addicted
To do that, you have to do the following:
1) Go to C:\ProgramData\TruckersMP\data
2) Copy "ats", "ets2" and "shared" folders
3) Paste them in C:\ProgramData\TruckersMP\data
4) Rename them to "ats_mod", "ets2_mod", "shared_mod"
5) Go inside "shared_mod" folder
6) You'll see images that are named in the following manner: "server_item_0", "server_item_0_sel" etc. You have to replace these images.
Have a nice one!