Sharing tickets from within the app is now support in the Zoho Desk Android app
Hello,
In the latest version of the Desk Android mobile app (v2.4.31), we have brought in support for 'Share Ticket' from within the app. Users can share tickets with other departments for their agents to collaborate their work.
Agents from other departments can access the tickets shared with a limitation which will work based on the permission levels given to their departments.

Please update the app either from the Play Store or using the link given below:
Zoho Desk mobile app - Play Store
Regards,
Roshan