Can I use a USB to USB-C adapter with an iMac's Thunderbolt ports?

I am planning to buy a new iMac that is listed as having 4 thunderbolt ports. I will need to connect regular USB to it. There is a usb to usbc adapter available, does this fit? I find Apple’s cables a puzzle.

[Re-Titled by Moderator]

Original Title: Usbc and thunderbolt