I’m having some issues (I’m a beginner, so if it’s something I missed I’m sorry) with the header in the Shop page. There is a text in there that I haven’t put there and I can’t find where to remove it.
As for your Shop page issue, I can’t see any text you’ve marked in the screenshot when I visit your website now. Have you resolved it by now please? From the screenshot it seemed to me like there are some empty lines in the content of your Shop page. To remove those, just edit your Shop page in WordPress admin and remove all the text and empty spaces from the page content.
If you want to edit the “This is where you can add new products to your store.” text next to Shop page title, use the page excerpt field.