Hi,
Here's the basic system in Canada. The time off that you are entitled to each year is commonly called 'vacation time'. The term 'vacation' does not necessarily suggest travelling, but rather leisure. You might just stay home and watch TV for two weeks.
Your boss is not entitled to know what your plans are for your vacation, and does not really care. You are entitled to the time, no matter what your plans are. However, you do have to consult with your boss as regards when you can take the time during the year.
If you want to go to a wedding, or visist your sick uncle, you typically do this by using a few days from your vacation allowance.
As we have discussed earlier, different countries apparently have different systems, so people should write letters based on the system in use in their particular country.
Best wishes, Clive