To reply formally to an email acknowledging the receipt of the original message, you can use a concise and polite response. Here's a suggested reply:
Subject: Re: [Original Subject]
Dear [Sender's Name],
Thank you for your email. I acknowledge the receipt of the message.
If you require any further information or assistance, please feel free to reach out.
Best regards, [Your Name]
This response is brief, acknowledges the receipt of the email, and leaves the door open for further communication if needed. Remember to replace "[Original Subject]" with the subject line of the initial email, and "[Sender's Name]" and "[Your Name]" with the appropriate names of the sender and yourself, respectively.