FIrst thing is
do not leave food or crumbs or food wrappers in the car. I'm always amazed at how dirty some people's cars are with food and wrappers strewn all over the place including under the seats. Second is to try and block off any opening 1/4 inch or larger where they might be getting in. One very common place they gain access to the cabin is the cabin air circulation motor intake in the engine firewall. There is a fairly large opening for the cabin air circulation motor intake that doesn't typically have a screen on it.
See my post at the following link for some examples pictures of that engine firewall opening for the cabin air circulation motor on a 05 Corolla. And what I did to deal with it.
https://www.toyotanation.com/thread...-corolla-how-to-get-to-fresh-air-intake-under-wiper-blade.477441/#post-13020258
In my case they were getting into the cabin air filter and chewing it up and they were getting into the engine air filter and chewing that up as well. I duct taped some window screen mesh over the openings and so far seems to have stopped the mice infiltration.
One can try all the usual methods if a mouse is already nesting inside the cabin. Bunch of snap traps or similar baited with peanut butter, peppermint oil on cotton balls scattered in the car, dryer sheets, Irish spring soap bar shavings, etc. But none of those methods work unless one also cleans out the car and blocks off common cabin entrances. If the vehicle is parked in a garage also put down traps under and around the car in the garage to catch any living in the garage itself.
And finally use the forum search feature, LOTS of past discussion of mice in vehicles being discussed here with various ways to try and deal with it.