What car charger can I use for my 2018 Macbook Pro 15”

There are many USB-C power adapters on the market. You should search for a USB Power Delivery (USB-PD) certified lighter adapter.

InnovativeApple wrote:

What car charger can I use for my 2018 Macbook Pro 15”, or how can I charge it in my car... similarly my new ipad pro?

USB-C car charger for MacBooks? Satechi delivers - 9to5Mac

That is one of the better ones on the market. It doesn't have the same power output as the AC power adapter that comes with your MBP, but there shouldn't be a problem with that.

Have you checked to see if your car has a 110V outlet? Some do.

We have a 2014 Toyota Sienna and a 2002 Toyota Avalon. Both have 110V outlets that will handle up to 100W devices. On the Avalon it is not in plain view, tucked awkwardly under the dash. I would not have known I had it without either reading a rather thick users manual or, what I did, crawling under the dash to reposition a bit of the carpet that had slipped. Looked up to one of those Voila! moments.

The Sienna was easier; it was on the center console's rear face for the convenience of the middle-row passengers. It also has another 110V just inside the tailgate. Heck, if we lost power to the house we could run our tech in the Sienna!

Either vehicle will charge my 2012 MBP with its 60W charger with no issues.

A notebook computer requires much more power to charge than your iPad. Looks like a 2018 15-inch MBP requires an 87W charger. However, history shows a charger with a little less wattage like the 72W model Leroy linked can still charge, just at a slower rate. Should be OK.