How to Add a Category to YouTube Videos
Ensuring your videos are properly tagged is an integral piece of your video optimization. One of the tags you can set is the category of your video. For most businesses, the category will fall under the How To category or People and Blogs. But depending on your industry there are any number of topics to choose from. Making sure you choose a relevant category will improve your search rankings.
You can set the category for each video individually, but if you plan on uploading consistently, I recommend setting a channel default. From your video manager, click on channel and then go to upload defaults. From there you can set and save your video category for all of your video uploads.