In Zoho CRM the native integration to Zoho FSM appears to use Zoho Books in the middle to sync the Zoho CRM Contacts and Parent Accounts to Zoho FSM as Customers and Companies.

I have gone ahead and set this up although in Zoho CRM we have not been using the Parent Account field so none of the Customers in Zoho FSM have Companies at the moment and no Companies have been created in Zoho FSM yet.

There also appears to be this integration in the Marketplace for Zoho CRM to Zoho FSM: https://www.zoho.com/fsm/features/integrations/zoho-crm.html

I did not enable this and not sure if I should.

In Zoho FSM I have enabled the Zoho Desk Integration. I am able to create Work Orders from a Ticket in Zoho Desk.

In Zoho Desk I have the Zoho CRM enabled with a 2 way sync for the Accounts and Contacts.