What does adding alternative text to images in WordPress mean

When publishing a Post in WordPress, after uploading an image, there is a field to fill in the 'Alternative Text'. What is the purpose of this alternative text?

The Role of Alternative Text

The purpose of this alternative text is to tell search engines what the image is roughly about. Because search engines, unlike humans, cannot see what the image contains; they only know if you tell them. After adding it, you can see the alt tag in the website's source code, as shown in the image below:

What is an ALT Tag?

The alt tag is essentially the text prompt for an image on a website. Including keywords in the alt tag is a good method to improve keyword ranking, but it's important to note that it does not increase keyword density. Reference: https://baike.baidu.com/item/alt%E6%A0%87%E7%AD%BE/9682416?fr=aladdin

How to Automatically Add ALT Tags?

Naibabiji recommends manually filling in the ALT tag when uploading images. If you find this troublesome, you can also consider using a Plugin to automatically add ALT tags, for example:WordPress automatically adds ALT and title names to images