I am using an AsRock x370 Taichi motherboard, and Ubuntu doesn't seem to be able to detect the embedded 802.11 module. It looks like it is able, however, to use the bluetooth module. The WLAN module's manufacturer is Intel.
Another lead is that the wifi adapter may default to the off state as shipped. The ASRock X299 "off" and can be set to on in the bios under
Advanced >> Chipset >> WLAN (Change "Default" to "Enabled")
Hope that helps.
For those that stumble upon this question with the same issue. I was able to solve this with the command given in cheche's answer to How do I get an Intel Wireless 3168 802.11ac wireless card to work?
apt install linux-generic-hwe-16.04