How do you add text to a video on YouTube?

There are several ways to add text to a video on YouTube:

Use video editing software: If you have video editing software, such as Adobe Premiere Pro or Final Cut Pro, you can use it to add text to your video. These software programs allow you to import your video, add text, and then export the edited video to YouTube.

Use YouTube's Video Editor: YouTube has a built-in Video Editor that allows you to make basic edits to your videos, including adding text. To use the Video Editor, follow these steps:

Follow Step by Step Guide 

Go to your YouTube channel and click on the "Video Manager" option.
Find the video you want to edit and click on the "Edit" button.

In the Video Editor, click on the "Annotations" option on the right side of the screen.

Click on the "Add Annotation" button and then select the "Speech Bubble" option.

Type in the text you want to add and use the options in the editor to customize the appearance of the text.

When you're finished, click the "Save" button to apply the changes to your video.

Use YouTube's Annotations Editor: 

YouTube's Annotations Editor is a standalone tool that allows you to create and edit annotations for your videos. To use the Annotations Editor, follow these steps:

Go to the YouTube Annotations Editor page.

Click on the "Choose Video" button and select the video you want to add text to.

Click on the "Add Annotation" button and then select the "Speech Bubble" option.

Type in the text you want to add and use the options in the editor to customize the appearance of the text.

When you're finished, click the "Publish" button to apply the changes to your video.
Keep in mind that annotations will only be visible on desktop and laptop computers, and not on mobile devices or tablets. If you want to add text to your video that will be visible on all devices, you will need to use a video editing software to do so.