Hello @Greg Bemis
Sure is possible.
You need install Azure Ad Sync on your onpremises environment, to sync AD credentials and password to your Azure AD.
Here's a document explain how to do step by step.
https://docs.microsoft.com/en-us/azure/active-directory/hybrid/how-to-connect-install-custom
I hope this is help you.
And if yes, don't forget to upvote and accept the answer
Regards