If you want your videos to sound good, you will need an external microphone. Microphones or mic for short, tend to be expensive till lately where more and more people start to make videos, and want to step up their game.
Fortunately, manufacturers started to make more budget equipment that sounds good for beginners. This microphone I reviewed, and demo in this video below might be just for you.
Listen to the sound samples of the budget microphone for YouTube video recorded into the smartphone here.
How to make videos with just your smartphone. Things to avoid.