To always send in RTF as opposed to Plain Text Select some text then to the right of Cut|Copy|Paste hit the arrow and format the Text as Bold Italic or Underline
The above would be useful if you use exclaimer on your exchange server to add disclaimers to your Company’s email
It is worth keeping the default ‘Sent from my iOS Devicename‘ to make people aware that you’re probably not in office at the time of sending the email