The blue slot is PCIe x16 and the black slot is PCIe x4
And you can install basically anything you want into them. This includes GPUs, network cards, sound cards, extra USB ports, or even a RAID controller if you want.
PSA:
Telling people to "RTFM" is not helpful and just discourages newbies.
If you can't restrain yourself, then don't reply.
The proper way to handle it is to provide an answer, perhaps even references, then KINDLY advise them on how to find the answers theirself in the future.
r/homelab is not the sub to gain basic PC or research skills, if you don’t have them then and the ability to do basic googling then you shouldn’t be posting here. This is not r/techsupport