Automating our service sign ups -> Klaviyo

We’re a service based business, not an e-commerce business which means we can’t have the simple plug and play.

How can we make it so as a user signs up and takes action through our service (mobile app) they will be added and segmented automatically into Klaviyo?

Example:
Johnny signs up for our service, he then onboards and selects ‘driver’ as his user type. He hangs around and doesn’t do anything, but we engage him to post his ride offer. He does and soon gets a ride request, days later they complete the ride. We want to segment him into signed up (engage them to onboard), then once he’s onboarded we know his user type (driver) so now it’s time to push driver engagement material to them so they become an active community member. He completes a ride so now we want to put him into another segment where he we can sort by rides completed for example.