By default, AKS will provision a standard SKU load balancer to be set up and used for egress.
However, the default setup may not meet the requirements of all scenarios if public IPs are disallowed or additional hops are required for egress.
To read more about the other egress options, see here :
https://video2.skills-academy.com/en-us/azure/aks/egress-outboundtype#outbound-types-in-aks