The button: add to cart has this text on it.
How can I replace all the text with a plus sign and a cart icon of category pages, just like this shop has: https://www.bol.com/nl/nl/l/babyverzorging/11306/
Sorry to say but right now there is no option in Theme Settings available for that. It requires Customization and this is beyond our limitations and support policy scope. Hope you can understand our limitations.