To add a booking for one or multiple days in Yearly View, go to View - Yearly Overview (for adding bookings in Yearly View in Team Manager, see Add Multi-cell Bookings in Yearly Overview in Team Manager). Select the cells you want to add bookings for and click Actions -Add booking (or right-click - Add booking):
Adding bookings for multiple days in Yearly view in Astrow Web
The functionality of self adding bookings for multiple days is available only with an ESS license and the Self Edit Bookings permission. It is also very important to set in Configuration - System - Application config the maximum days for self-edit bookings/absences for the past and future.
For more details related to the number of days in the past/future to edit bookings, see System Settings.