How do I show text on an image click?

I want to place a banner (image) on my homepage and when a user click it text will appear underneath – not a caption but a few paragraphs about what we do. But I want it hidden unless someone clicks on it. When they click on the image again it will disappear.

I have spent hours looking at the ShowHide plugin, accordions, toggles and various code but for the life of me cannot figure this thing out.

Points to consider (which I think are throwing me):

I need the image to be responsive so I am assuming this means CSS? I need the image to be 100% on homepage on desktop – so site width but still be there albeit relatively sized on a mobile or tablet.

I don’t want any +/- type icons or it to be a lightbox or in a container etc as I want the text to be in the content of the homepage for SEO purposes.

If anyone can help I would very much appreciate it. Thanks!