Bolt
This is probably the most popular app, with the most drivers. Until recently its been cash only. Some drivers may not accept the in app credit cards. The fares are also the cheapest!
Grab
https://www.grab.com/th/download/
Grab is a do everything app, from ordering food, to taxis. The Taxis in grab are less numerous and more expensive, but they always accept credit cards.
Movmi
This is a ride sharing TukTuk for Bangkok areas only right now. You load the app and it shows you pick up and drop off spots in your small area. You can book 1-6 seats in an Electric TukTuk and they will route a tuktuk to come pick you up in a few minutes. This is a very inexpensive option, great when its not raining. Think of this as the last mile transportation from any BTS station. ___
If you are in Chiang Mai, there are also red trucks that are kind of shared taxis - you flag them down when you need a ride, and the back can hold 8 people or so (depending on baggage, and how tightly you cram in). If they already have passengers, they may not take you if you are going a completely different direction, but it’s usually not an issue. The prices are fixed, and are printed on the side of the trucks - at the time I was there, it was 50 baht per person to take you anywhere in the city (if you need to go outside the city, you can negotiate a price with the driver). Some of the drivers may try to get you to pay more - just confirm the price ahead of time, and point to the price on the side of the truck if they try to object.
I believe some other cities may have similar trucks, but they were primarily a feature of Change Mai while I was there.