An image alt tag offers a text alternative to an image on a website. It describes what the image is, so if for any reason the image is broken or does not show due to a slow connection, the alt tag offers text detail about the image. Essentially, it doubles as a second image title.
An image alt tag is useful for SEO, to help identify images on your page and increase page ranking by allowing your images to show up better for a variety of image searches. In addition, alt tags are used by screen readers and browsers used by those who are visually impaired, to tell them about the image.
This is where your Alt Tag goes if you are using a WordPress website.