Download Microsoft Remote Desktop from the Mac App Store. Click the blue "App Store" icon in your dock.
Once you've accessed the Mac App Store, use the search bar at the top right of the screen to search for "Microsoft Remote Desktop." The first search result should be what you're looking for. To begin the download, click the blue "Get" button. This is a free app.
Next, open the application by clicking through the grey "Launchpad" icon and clicking on the Remote Desktop app icon. Upon opening the app for the first time you will see this dialog box.
Select “Add PC”
Note: At this point you'll need to enable remote access on your target PC. For a Windows 10 machine, the fastest way to get this done is to search for "Allow remote access to your computer" and click on that when it comes up. Under the "System Properties" box under the "Remote" tab, the button labeled "Allow remote connections to this computer" should be selected.
Click on “Select Users” and add your userid if not listed.
Next, Click on the "Computer name” tab to find the full Windows Machine name.
Enter that name in the PC name field of Remote Desktop app on the Mac.
Enter your Credentials to login to your PC as union\userid and then your password and Select Continue.
Select Continue to initiate the remote connection.