Google Cloud does not have first-party managed Kafka service. For messaging, you can mostly use Cloud Pub/Sub. If you need capabilities of Kafka, then you can run Kafka cluster either as a third-party managed service (e.g., from Confluent Cloud), or run it on Kubernetes with an operator.
Confluent can create managed Kafka clusters using Confluent Cloud on Google Cloud. Check out the Confluent Cloud's Quickstart documentation for more information.
If you want to run Confluent's Kafka platform yourself, you can use the Confluent Operator, which can provision Kafka clusters on Kubernetes Engine. See Confluent Platform on Google Kubernetes Engine documentation for more detail.
You can run Kafka in Kubernetes using the Strimzi Operator. See Strimzi Quickstart documentation and the more detailed Strimzi Quick Start Guide for more information.