When replying to somebody on email it is always a good idea that you change the font colour or even type so that the person who receives email can distinguish between his and your comment. In Outlook this can be achieved by going to
- Signature > Personal Stationery > Font
You will need to select the check box which says Pick a new colour when replying or forwarding.
There is one more option here which you can also use., Mark my comments with a different text which could be your name too.
Related : How to keep different signature for different account
