As of July 1, 2019, Back to My Mac service will no longer be available in any version of macOS. You can use these alternatives for file access, screen sharing, and remote desktop access.
• Access files across your devices with iCloud Drive: When you turn on iCloud Drive, your files automatically upload to iCloud, where they’re safely stored and available on all of your devices. Turn on the Desktop & Documents Folders option in iCloud Drive to store them in iCloud, too. Now you have access to all of your files, on all devices, at any time.
You start with 5GB of free iCloud storage and can upgrade any time from any device. iCloud Drive has an individual file-size limit of 50GB.
• Access your other Mac with screen sharing: If you have more than one Mac, screen sharing lets you use one Mac to view and control your other Mac remotely. This means you can open, move, and close files and windows, and use apps — even if you’re in another location — so you can always get what you need. Learn how to set up and use screen sharing.
• Manage your Mac remotely with Apple Remote Desktop: If you have more than one Mac, Apple Remote Desktop also lets you run apps and work with files that are on your other Mac, even if you’re in another location. So if you want to use an app that’s only on your other Mac, you can. Learn how to use Apple Remote Desktop.
Source: Apple Inc.
MacDailyNews Note: Apple Remote Desktop (US$79.99) offers more remote management capabilities than screen sharing, including installing and configuring apps, helping remote users, and creating detailed reports.
Screen sharing and Apple Remote Desktop screen sharing are compatible with Virtual Network Computing (VNC).