Many customers always have trouble adding to cart, where the vast majority use phones to make purchases. Apparently phone browsers have a navigation bar that does not allow to see the add to cart button. I attach a video link, this is a very problematic problem, the only solution is to give the link directly to the customer which is quite redundant, this site is embedded to Google Sites a tool used to gather all the content of my business and give the link directly from the catalog would discard the function that has Google Sites in my business.
A possible solution is that from the administrator or configuration of the site, this the option to make the cart bar is fixed or placed before the product description and so the customer on the phone will not have problems with the navigation bar of your browser.
Clearly this is a solution for developers to consider. I hope you see my idea about the problem thank you.
the problem here is that the google sites link embed is not screen size friendly, no matter how many adjustment made, there are multiple devices with different screen size, so the cart will not always show, and sometimes the user are not familiar with iframe websites that they have to scroll to the bottom.
the solution i made for google site is just make it open a new tab to your store link whenever a menu was clicked.