Docker operates using a client-server architecture where the Docker daemon runs as a root user. This Docker daemon creates, runs, and manages Docker containers. When compared to Docker, Podman adopts a daemonless model.
Both Docker and Podman deal with container images. Building your own container images allows you to customize containers for your needs. Then, you can create containers using the custom image. Docker images are stored in Docker Hub by default but can work with other registries.
Docker and Podman both have extensions. Docker Desktop contains many extensions as part of the Docker Desktop tool. This allows extending Docker with new and cool functionality from third-party solutions. You can install tools like Headlamp and Kubescape to name a couple.