A couple of our clients have used a service called Pure Chat, which is easy to use, and they offer a free plan for light usage.
There are lots of other live chat providers available too (e.g. Formilla), so it’s worth having a search around to find a service that meets your own requirements.
We recommend you sign-up for an account yourselves directly, as you may need to enter some contact or billing info during the registration process.
Then, if you need us to do any work to integrate the chat service into your website, we can of course help with this side.
If you need any support using your live chat service, we suggest reading your provider’s help guides or contacting their support team.