XMind does not support synchronization currently.
For XMind for iOS, users can use the synchronizing system of iOS to sync the files between desktop and iOS mobile. We recommend users to use iCloud or Dropbox to sync the files.
Below are the steps of how to sync between XMind desktop and XMind for iOS. (iCloud as an example.)
1. Upload your desktop mind maps to iCloud,
2. Launch XMind for iOS,
3. Enter Browser > Location,
4. Tap iCloud Drive,
5. Find the maps you uploaded from desktop.
Please note that only iOS11.0 or later version supports synchronization.