Commonly called headers, not sure if there's a more 'proper' name. Square pin, .1" pitch (or 2.54mm, or 100mil), typically gold plated. Hopefully this link will retain the filters I've selected.

IIRC the extra pin on a 4 pin motherboard header may report if the fan has totally stopped, like a failure line, to tell the mobo to shut the CPU off. I've got an old 4 pin fan here from a '94 ...

This will allow you to, for example, add USB 3.2 Gen 2 USB-C ports, where your PC might only have USB-A ports built-in. But if you're just needing a way to connect more USB devices, you can always ...

ASRock has five fan headers on this motherboard. The CPU fan header is circled in red and supports PWM fans. The other four circled in blue work with either 3-pin DC fans or 4-pin PWM fans.