Alternative text, or alt text, describes the content of images, graphs, and charts. It should be added to every image that conveys meaning.
1. Select an image, drawing, or graphic in your Google Docs. Right Click and Select All image options
2. Right click and select Alt text and Enter a Description.
You can also press Command+Option+Y on a Mac, or Ctrl+Alt+Y on a PC.
3. Click Advanced Options and Input a Title
If an image is decorative, describe the image as "decorative image" for both Title and Description. Leaving them blank could run the risk of the screen reader trying to interpret the image would could prove messy.