.Rar file won't upload

Hello Everyone, 

I got some brushes and stuff, but instead of them being in the format I'm used to, they're in .rar format. I can't upload them. I did search for an answer but the most recent one I could fine was from 2017. I don't know if I missed something, though? Anyway, I would really like to use these brushes. How can I upload these? Thank you for any help!