You have added these icons as one image containing them, you need to edit an image in any image editor, such as Photoshop or else, you can use this free online service: https://www.photopea.com/
You can find the image in the Theme Settings > Footer > Copyright.
If you have any questions please feel free to contact us.
should o make one image an time ? and how to put all image together at the end ? should upload them to library and copy every link and put them in the footer – copyright