Keywords play a big role in ranking videos on YouTube. If you can't choose the right keywords for your video, your video won't show up in the search results, and if you don't show up in the search results, it won't have a view or a subscriber.

You can do keyword research through many tools

Ubbersugggest:

Keyword.io:

Keyword planner:

VidIQ:

With these, you can find the desired keywords. But these keyword tools will not be of much use to you for ranking on YouTube.

We all make the mistake that we copy from the keyword tools and select the video tag But in fact, we do not research whether this keyword is being searched on YouTube or whether this keyword has been ranked. For this, I would suggest you find the keyword for your video through organic.