When you're making a YouTube video, your target audience is the group of people you want to watch it. They're the ones who you think would be most interested in what you have to say or show. Knowing who your target audience is helps you create a video that speaks directly to them, using language and topics that they'll relate to and find interesting. By targeting the right people, your video will have a better chance of being successful and reaching your desired outcome.
Some examples are: Beauty and fashion enthusiasts, people who want to learn cooking, pet owners, sports fans, art lovers, etc.