Hello,
If you want to push your model to the Hugging Face Hub you can do this directly inside the train.py as shown here: notebooks/sagemaker/14_train_and_push_to_hub at master · huggingface/notebooks · GitHub
or you need to download the model.tar.gz and push it to hub afterwards Documentation. There is currently no method inside the sagemaker-sdk to push models to the hub after training.