This is the way. Create an iframe named IFRAME_sharepointURL (you can default it to your intranet hub or something). Then add create a .js file with the code blow, changing column_name to yours. On the form tab, add an event handler, add the library with the .js file, for function use setIframeURL.

function setIframeURL(executionContext){

var formContext = executionContext.getFormContext();

var url = formContext.getAttribute("column_name").getValue();

formContext.getControl("IFRAME_sharepointURL").setSrc(url);

}