Upload image is description features box

How do I attach an image to a template in the Description box
I uploaded the image to one of the image upload sites and then I made a embed to it as HTML code. Is this method true or what?

Like the description at this
https://www.codegrape.com/item/auril-creative-one-page-wordpress-theme/14136
he include image at his description then text
how i can do this ?

You need to upload images to free images hosting websites like:

https://postimage.io/

Then, copy image url to img HTML tag.