There is an annoying default setting in Gmail that puts your signature you have created at the bottom of the reply message. Apparently, there was enough complaints about this that Google has now allowed you to have your signature BEFORE the reply message but you need to tick a button in your Gmail settings to do this. You would think the default would be that the signature is placed BEFORE the reply message, but the developers think the default should be AFTER the reply message. So if this default setting annoys you, here are the steps to change the default setting:
(1) Log into your Gmail on the web
(2) Click on the Gear icon near the top right corner and choose SETTINGS
(3) Scroll down to SIGNATURE and you should see the following and tick the check box at the bottom:
