How to add "alt text" to your images
Adding alt text or alternative text to your images is essential. Not only is it used to make the page more accessible for those with visual impairment, Google has stated publicly that alt text is an important ranking factor. Not to mention, it is an opportunity to add important keywords to compliment the narrative theme of the page/post.
What should my alt text say?
Firstly, I strongly suggest you avoid keyword stuffing (repeating the same words across a page post or website) as this is frowned upon by Google and your website could be penalised. Instead, you should think of a sentence or two that adequately describes the content of the image.
How do I add alt text?
Content management systems, such as WordPress, generally make it easy to add alt text when uploading an image. You can also access the same panel, in WordPress, by clicking "Edit" on an image in a post while editing in the back end of your website.


How to add alt text to a website manually (useful for static/HTML sites)
If you have a static site or the CMS doesn't easily let you add alt text, you can add an alt attribute to your image by inserting the following text and placing it into the image tag: alt="Your text goes here"
It should look something like this: <img src="yourimage.jpg" alt="Your text goes here">