The beautiful thing about SaaS products is that they are so scalable: every customer gets the same product, with little to no customizations. That makes Customer Service straightforward as well, as customers are likely going to have the same problems.
There are a few methods that will let you help many of your customers at the same time.
Synchronous tools such as chat widgets will allow you to be there when people are experiencing real problems that they can’t solve themselves.
Asynchronous tools such as automatic responses and resolution chatbots will help those customers who just need a nudge. Finally, self-help tools like knowledge bases will allow you to distill your 1-on-1 conversations and problem resolutions into articles that can be read and followed by every future customer that runs into trouble.
Using a system like Intercom that interweaves all of these kinds of tools will increase your efficiency: you help a customer, then write the article, and the next time anyone asks, they get a suggestion to read it. Answer once, help a thousand times.