The Axsy Field Service App is powered by Salesforce's Field Service Lightning Objects. As such, creating and managing Work Orders and Service Appointments are all done via Standard Salesforce Objects. 

The Axsy Field Service App supports many other features from Salesforce – e.g. Service Reports Generation, Inventory Tracking, Resource Absence Management etc. – all of which are also controlled via Standard Salesforce Objects. 

For a broader overview of Salesforce's Field Service Lightning, please see here: 

Field Service Lightning