I receive multiple questions a day on my iPhone and need to send the same reply to them. If my phone is on and open and I read the text, is there a way to send the same reply with out having to type it out?
Welcome to Ask Different! I know of no way to do this internally in imessage. A workaround, which you may have already considered, is to open the notes app and leave it open to a new note page. Every time you reply to a text message just copy it and paste it in the Notes page. Now whenever you receive the same message, you can copy and paste from Notes. This is probably more work than you want for short replies but if your replies are many lines long this would help a lot.
Someone else may answer this question with a better answer but in case they don't you have an easy workaround.