Here is some useful information on mobile instillation.
www.K0BG.com
Also, this web site is for various vehicle mounts.
https://www.breedlovemounts.com/
You can also look at some of the stores online such as Gigaparts, HRO and Universal Radio.
I particularly like the mounts and antennas from Diamond, but everyone has their own preferences. If you can, try to attend a local ham radio show. I go to the one in Dayton OH every year in May. There is always a ton of stuff to see! Good Luck!