If embedding the Usersnap QA widget on your site is not an option, using one of the Usersnap's browser extensions is a good solution. You can annotate on your website without changing your template code.
Google Chrome users can find the Usersnap extension in the Chrome Store: Google Chrome Store
Firefox users can find the Usersnap extension in the add-ons directory for Firefox: Firefox Extension
There are two ways to log into your Chrome and Firefox browser extensions.
Once your browser extension is installed and configured, you can create a screen on any website by clicking on the Usersnap icon on your browser toolbar.