Is earned annual leave a common HR practice?

Would like to check was earn for your annual leave a common HR practice?

For example you are entitle 12 days leave per annual. You wish to take 8 days annual leave after you had work 6 months for a company and the HR only allow you to take 6 days as annual leave and the other 2 days as unpaid leave even though you had never consider of resigning.

Any governing rule regard to this issue?

It governs by the leave policy of respective companies. Some companies practice earned leave as of the month of leave application, while some companies practice bloc leave for the employee’s year entitlement.