can I share folders with other people?

Define 'other people'

There are many ways to share folders. The specifics depend on the details.

Are you sharing with people you know?

Are you sharing with people on your local network?

Random strangers on the internet?

Are the other users all Mac users? Windows users? mobile users? unknown?

What are your requirements from a security/access control manner?

All of the above result in different ways of 'sharing a folder'

Yes. See: Share folders with iCloud Drive - Apple Support