@Prasanth Kothuri sending attachments in automated email tasks is difficult since attachments are generally considered a security risk. Is there any reason you couldn't send just a link to the S3 object in your email text message?
I remember I had a similar use case in the past and solved it using presigned URLs in S3. Basically, you send a normal email message, but within your message, you send a presigned URL that allows downloading the S3 object with a single click from within the email with no extra authentication because the URL is already presigned to be authenticated for up to 6 hours. LMK if you are interested in seeing an example.