Not sure why you would think you couldn't, but yes, Raspbian is the official OS of the Raspberry Pi computers. The latest version works on all models, past and present, and is easiest to install by writing a Raspbian image with Etcher.
Download the latest official Rasbian image release here: https://www.raspberrypi.org/downloads/raspbian/
Download the Etcher image writing software here: https://www.balena.io/etcher/
Use Etcher to write the image to your micro SD card directly from the Raspbian .zip download (do not extract the image first).
You could also use the NOOBS installer, but writing images with Etcher is faster and easier (and less troublesome for most people).
My mind is like a browser. 27 tabs are open, 9 aren't responding,
lots of pop-ups...and where is that annoying music coming from?