you're in a dangerous spot between "not knowing enough" and "wanting to know too much"
So for a normal user (not buying the most powerful CPU from a company, not overclocking, etc.)
Here's what you usually want to keep an eye out for:
The "B" Series boards (B650 and B660/B760 currently for AMD/Intel) are solid middle of the road options, and support enough features to make most people happy.
The *70 (AMD) and *90 (Intel) are usually slightly higher end chipsets, but also more expensive. But if they're a reasonable price, they're also a damned good option.
Otherwise the only thing to really look for:
Does it have enough IO for you?
IO to look out for:
USB C, USB A, What type of USB? Thunderbolt? Etc. (WIFI onboard if you need/want it)
Also an important one: M.2 Slots
Beyond that, not nearly as much matters, as most people add a GPU and nothing else to PCIE Slots.
If you're wanting to buy high-end, there's more to know, but that's a dangerous (and expensive) path to follow, so don't do that unless you know you need to