I recently upgraded to a 2020 Macbook Air (having misplaced my trusty 2011 Macbook Air during a fire evacuation).
Simple USB-C to A adaptors are very inexpensive.
If you want to do other things, like drive an external monitor or projector, a UCB-C/thuderbolt 3 dock is needed. The graphics card is capable of delivering 6K @ 60Hz, but most adaptors down-grade it.
Probably the best docks are made by CalDigit.
The $250 one is apparently the best one you can get, and if you have a displayport monitor, it is ideal. It also has an optical audio out, ethernet in, and many other connectors, and is also a stand-alone power supply.
They have a more sanely-priced portable docs ($120) with either displayport or HDMI out.
I jsut got a portable dock from Satechi
for about $90. The HDMI only outputs 30Hz, but that is good enough for a projector. (I got a separate $12 cable -- thunderbolt3/C to displayport, which gives me an undegraded connection for an external monitor).