It is also possible to set personal calendars for certain team members and resources. This will help in the calculation of task estimation and duration and in workload and costs management.
Click on the Team & Resources icon 1 on the left sidebar. Choose the resource, click on the three dots button to its right 2, and select Personal calendar 3. 
In the Resource calendar, you can customize the working schedule 1 for a particular resource if it differs from the rest, set working hours 2, and add exceptions 3 like Days off and Custom days.
As an example, you can note vacations or reduced hours established in the contract for a particular project member. 