I work on the Support mobile app but I can't see the ticket sharing field on a ticket in the mobile app. Can I use ticket sharing in the Support mobile app?
No, ticket sharing is not available for the Support mobile app. A workaround is to use a trigger to share a ticket with another Zendesk account when a tag is added to a ticket. For more information on how to use business rules to share tickets, see the article: Using business rules to share tickets (Professional and Enterprise).