Do you want to find mod that already exists or do you want someone to create it? If you are requesting a mod, you should post it in ideas and suggestions. Also, what exactly do you mean? Semi? Pickup?
If you mean first trailer mod for t series, you can get it here: https://beamng.com/resources/reworked-semi-trailer-by-gmaksi83.983/ I don´t recommend installing it as it may break t series because it is outdated. It was made when t series was in development way before years, and I updated it in 2016. But as we have official dryvan trailer now, there is no reason to update it again.
What? As I said, there is official dryvan in game by default. Just open vehicle selector and scroll down.
So, you want someone to make a dry van trailer skirting mod. You could have been a bit more descriptive instead of saying "i want see truck and trailer mod" on the original post since there are many mods for the dry van trailer (and trailers in general) and the T-Series semi and D-Series pickup.
That doesn’t exist currently. If you want the mod to be created, put it in the ideas and suggestions area of the forums. That way someone will see it and maybe make it.