I got a question the other day from a Tapatalk user about why replies sent from that app always include a quote of the message before it. Here's the skinny.
If you need to quote (copy/repeat) a previous post in your message, click the Reply link at the bottom-left of the post your want to quote. Most of the time, quoting a previous post isn't necessary, but when it is, this is how you do it.
If you just want to post a general reply without quoting a previous post, click the reply icon at the bottom-right of the screen.