Automatically display set text based on users composition

[Rhys]

Hi, im trying to do something really simple, trouble is i
dont know what the feature's called to be able to search
for tips on how to do it.
Basically in outlook messages, when a user begins writing
a sentence e.g. "in the terms of" i need a tag to pop up
that allows the user to press enter and then the
remainder of what they will want to type in will be
inserted in, its a yellow tag that comes up above the
words. i dont know where it needs to be created and
enabled.

Cheers,

Rhys.