5. Add Metadata to Files
You'll be moved to a series of forms - one form per file.
This is where you can add all of the metadata for your files in one shot, which is actually a pretty big time saver.
Name field = this is the name of your file as it appears in the Media Library's administrative file panel. Establishing and maintaining a smart naming convention can really assist you in the long run, especially where media updates are concerned.
Alt Text field = this appears for images and should always be addressed. The text in this field is what a screen reader uses to inform a visually impaired audience member about the content of the photo.
Title Text field = this text will appear as a tool tip when your audience hovers over a file and holds there for a second.
After your metadata is completed, click the Save button.