How to read the used volume from a burette?
It depends ;-)

The scale on a burette typically is ascending from top to bottom. With other words: zero is close to where you fill your $\ce{NaOH}$ solution in, the largest value is close to the valve. The total amount added (to your vinegar) is the difference between the final and the initial reading.

But if your burette was initially filled up to the zero mark, this would just mean to subtract zero from the final reading (which is just the final reading).