Azure Container Registry implements Docker's content trust model, enabling pushing and pulling of signed images.
To push a trusted image tag to your container registry, enable content trust and push the image with docker push.
To work with trusted images, both image publishers and consumers need to enable content trust for their Docker clients. As a publisher, you can sign the images you push to a content trust-enabled registry.
Reference:
https://docs.microsoft.com/en-us/azure/container-registry/container-registry-content-trust