how to link between S3 and RDS

S3 does not support server side scripting. It can only host static pages.

Php is dynamic content which requires server side scripting which will not work in S3 bucket.

What your trying to accomplish is not technically possible.

Amazon S3 is a storage service, and it's typically not used to host server-side scripts such as PHP. PHP scripts require a server to process requests, and S3 is not designed to serve this purpose. Instead, S3 stores and retrieves static files like HTML, CSS, JavaScript, images, etc. So how do you do that on AWS? You can:

1. Host your PHP form on an EC2 instance, not S3.
2. Install a web server (like Apache) and PHP on your EC2.
3. Ensure your RDS security group allows connections from your EC2.
4. Use PHP's mysqli or PDO to connect to the RDS and store the form data.

I hope this helps