Access to S3- thousands of users

Hi Team,

I have a scenario where some of our end customer should be able to upload some files to s3. These end customers are thousands in number. How can I provide access to these customers without having to use SSO or any other.

Is there any service that is offered by AWS to provide access to S3 for thousands of users without having to manually create login links and all.

Any leads are appreciated.

Thanks