@Nitish Kumar Welcome to Microsoft Q&A Forum, Thank you for posting your query here!
I understand that you want to translate a document using Azure Translator without uploading it to Azure Blob Storage. However, as per the current Azure Translator API documentation, it requires the documents to be in Azure Blob Storage.
So, an active Azure Blob Storage account is required to use Document Translation.
Also note that, Our Document Translation REST API mentions about the requirement of having Azure Blob storage.
Workaround:
You can download the files from S3 to your local box and use this MicrosoftTranslator/DocumentTranslation
tool to perform the translation:
https://github.com/MicrosoftTranslator/DocumentTranslation
This tool makes use of the Azure Document Translation service. This app provides a local interface to that service, allowing you to translate a locally residing file or a folder, and receiving the translation of these documents in a local folder. The tool uploads the local documents, invokes the translation, monitors the translation progress, downloads the translated documents to your local machine, and then deletes the containers from the service.
Hope this helps. If you have any follow-up questions, please let me know. I would be happy to help.