
This 365 version works the same as normal outlook albeit with a couple less addons.
When responded or drafting a new email make sure that you have the
From field visible at the top by going to
Options and ticking
Show From
Select the
person you would like to send as in the
drop down list of the
From field


If they don't appear there, select Other email address... and type the person's name you would like to send as
Once ready, simple press Send

The signature will append at a server level as it leaves the system so don't worry if you can't see it when typing the email out