Hi @anushakh 

• Start document approval process via document details - No, this is not possible from mobile. You can view and revise document, but not start an approval process.
• Run custom events - No, as they are online database triggers, they are not supported in mWO at the moment. 
• How I can transfer my task back from mobile to desktop? - At what stage? You can cancel an assignment (it will only cancel the assignment, not the task), or you can return it when you complete or incomplete it.