How does Field Service Lighting work in Salesforce ?

Here are some of the things you can do with Field Service Lighting.
Create records that represent your field service technicians, dispatchers, and agents, and add details about their skills, location, and availability
Set up multilevel service territories that represent the regions where your technicians can work
Track the location and status of your inventory, warehouses, service vehicles, and customer sites
Schedule one-time or recurring work orders for customers, and add details about technician preference and required skills and parts
Create maintenance plans and templates to standardize your field service tasks
Generate service reports to keep customers informed about service progress

When Field Service Lightning is enabled, you gain access to a suite of standard objects that you can find in Setup and as tabs in Salesforce.