Definitely need more information. Are you sharing from mac on a network to a windows 10 machine? Or are you sharing between say a bootcamp install of OS X and Windows 10?
Here is how I share from my Mac Pro running OS X.10.5 to a laptop I have running Windows 10: First my user name and password are the same on all my computers. I say this as I do not have any of my macs listed in active directory on my servers so they are not "joined" to the network.
1. On the Mac Pro go to System Preferences -> Sharing -> turn on file sharing by select the services you need to share (File Sharing) then select the folders to be shared and the user. Select read only or read & write for each user.
Now click on Options -> and check both share ...using SMB and share ..using AFP (although windows will use SMB) -> Check the user account you will be using. Click done and close out of sharing.
2. On the Windows 10 machine open File Explorer -> select Network -> select the name of your mac -> select the correct user folder -> select the drive and right click to "Map a Network Drive" or you can create a shortcut on the desktop.
This can be done on a home network too. Here is an article that sort of (I could not find one specific to W10) walks you through it.
How To: Make Your PC and Mac Share Stuff Like Best Friends
Hope this helps.
Li\sa