First of all, go to AWS Console and access on search field: Amazon ECR. Access the option view push commands.
Execute the login command in your local console in your machine:
aws ecr get-login-password --region us-east-1 | docker login --username AWS --password-stdin<idaws>.dkr.ecr.us-east-1.amazonaws.com
After build your docker image before tag it:
docker build -t <namebuild> .
docker tag <namebuild> <idaws>.dkr.ecr.us-east-1.amazonaws.com/<namebuild>
Now you could push it:
docker push <idaws>.dkr.ecr.us-east-1.amazonaws.com/<namebuild>
You'll see in the list your image, now you could just refers the image name to others AWS services like Kubernetes.