Work Shift is referred to the schedule of work in your company. For example, your work shift may be from 0900 AM to 0600PM with a 1-hour break for lunch.
Each company has various policies and minimum and maximum hours governing work shifts. Each country also has its own laws on how many hours are allowed to a maximum a worker can work in a work shift in a 24-hour period. Please ensure you check local laws and regulations to be compliant.