Every time I click command r, the globe would pop up but then once it finish, it freezes on the white screen. What do I do?

For starters, go to > About the screens on your Mac as it starts up - Apple Support

and work thru the steps in the links for spinning globe and white/gray screen.

Then if nothing there helps you get the iMac up and running again?

You need to contact > Apple Support, an Apple Store or Apple Authorized Service Provider

Which exact model is your iMac? Which version of OS X or macOS is it running? Why are you trying to use Recovery Mode with this Mac?