Search engines aren't reading alt text in images

[sebastianserfas]

Hi there,
For example, my page's images do not use Alt text; I would like to use this type of Alt text that this site use . My website contains some SEO on every page and image. In my SEO, they are not tagged. The reason remains a mystery despite checking and modifying all the web pages repeatedly. Is it possible to fix this? Is my alt text hardcoded? In that case, how do I do it in JSON?