Simply replace the unfilled areas such as "[]" and "[date]" with your information.
Dear [name],
I would like to thank you for your web inquiry into our [products/services]. We are pleased that you have taken the time to learn more about us.
To help familiarize you with our line of [products/ services], I have enclosed a catalog, data sheets, and price lists. I have also enclosed information about our organization and its history. You will see that we have a solid reputation for excellence and customer service. You can be assured that our [products/services] are of the highest quality.
If you have any further questions, please feel free to contact me at [phone number] or [e-mail address]. We look forward to serving you.