Odoo does not have a recurring leave feature as standard.
If the goal is to setup "by default" a specific day as a time off in the planning, you can use the working times (you need to be in debug mode to see to access the working times models).
For example, you want to define that an employee work in 4/5 and will not work on Friday.
> go to "Payroll / Configuration / Work entries / Working Times" ;
> Create a new working times ;
> Delete the lines "Fiday Morning" and "Friday" Afternoon" from the working hours ;
> Go to the employee form ;
> Change the "Working hours" in the "working information" tab (choose the 4/5 you just created) ;
And then you can go in the time-off apps, Friday is always in grey (as the weekend days) and if the employeee try to add a time-off on that day, it will be not deducted from his available time-off days.