Apple Mac OS X’s free feature called Screen Sharing allows me to run a Mac computer to remotely access or control (including running the applications installed on the accessed, host, Mac) another Mac (the client) on the same network (wireless or wired). Screen sharing feature is helpful in many scenarios including remotely running, from one Mac (the host), the single licensed applications (like OmniFocus project management application or QuickBooks – an accounting application) installed on another Mac (the host).
I copy a short support article from Apple that explains the screen sharing setup.
I quote the entire article in the following:
OS X Yosemite: Share the screen of another Mac: Source from Apple’s web page: https://support.apple.com/kb/PH18688?locale=en_US
If you’ve been given permission, you can view and control the screen of another Mac on your network.
Before you start, make sure the Mac whose screen you want to control has screen sharing turned on. (For more information, see Share your screen.)
Open a Finder window. If no shared computers appear in the Shared section of the sidebar, put the pointer on the word Shared and click Show.
Select a computer, then click Share Screen.
If you don’t see the Mac you want, click All to see all the available computers, select the one whose screen you want to share, then click Share Screen.
Select how you want to connect to the Mac:
Guest: Connect to the other computer as a guest, which lets you view the screen but not control it. (Not available on all shared computers.)
By asking for permission: Ask the current user of the other Mac for permission to share the screen.
As a registered user: Connect to the other Mac using a valid login name and password. If the other Mac allows only specified users to connect, you must use a name that’s in its list of allowed users.
Using an Apple ID: Connect to the other Mac using an Apple ID. You must be set up in Users & Groups preferences with this Apple ID, on both this Mac and the other Mac.
If someone else is already connected to the Mac as a remote user, a dialog asks if you want to share the display with the other remote user (Share Display), or log in concurrently using a different user name and screen (Log In). Choose the option you want.
If you choose Log In, you will share the Mac with the other remote user, but you won’t share the same screen.
If you know the IP address or the DNS name of the Mac you want to share, you can also connect to it by choosing Go > “Connect to Server” in the Finder, and then entering vnc://[IPAddress] or vnc://[Name.Domain] in the Server Address field.
To find the address of a shared Mac, open Sharing preferences on that Mac and select Screen Sharing.