Hello melissa.hannam,
My name is Krzysztof, and I’m a member of LiveChat’s Technical Support. As a person who conducts a lot of screen sharing sessions with our customers, I think that this is a great question! 
When it comes to assisting our customers with more advanced technical problems, like lending a helping hand when adding LiveChat code to their website or diagnosing some system-specific issues with a desktop app, our go-to solution is TeamViewer app. It’s a powerful tool that allows us to not only take over our customers’ screens but also start a text, voice or video chat in case that our customers have any additional questions during the screen sharing session. What’s more, you can integrate the TeamViewer app with LiveChat window on your website, so that when your agent is chatting with a customer, with just a click of a button he can send him a detailed instruction on how to install and run a small TeamViewer app on his computer. No need to type the instructions manually or adjust the canned response to each new customer requiring a screen sharing session
If you’d like to see how well TeamViewer integrates with LiveChat window, check out our official TeamViewer tutorial, available here.
Also, I’ve got one more recommendation for you:
If your registration and scheduling program is available for your customer solely on your website and the screen sharing will not require accessing your customer’s desktop app, I can also recommend using our Upscope integration. By adding a simple HTML snippet to your website, Upscope allows you to conduct a simple screen sharing session, during which you will see your customer’s real-time movements that he or she takes on your website. And that’s not all – Upscope does not require an installation of any additional 3rd party apps, neither on yours nor your customer’s computer! If you’d like to learn how LiveChat integrates with it, check out yet another of our tutorials, available here.
Melissa, I hope that I was able to help! Feel free to shoot me in case of any follow-up questions regarding this topic or, if you have additional questions regarding LiveChat software, don’t hesitate to start a new thread! 