Audio out of sync after export

Hi there.
After Export, the audio’s out of sync with my lip movements.
Is this because I change Resolution to 1920 and 1080 before I export?
If I’m not supposed to do that, then how do I export in HD?

I make videos on YouTube.

Thanks in advance.

Other factors that can affect synchronization are the type of video and audio encoding - variable frame rates in particular can be problematic.