word attachments

Richard Stalman says - receiving Word documents is bad for you because they can carry viruses. Sending Word documents is bad for you, because a Word document
normally includes hidden information about the author, enabling those
in the know to pry into the author's activities (maybe yours). Text
that you think you deleted may still be embarrassingly present (see
here)

But above all, sending people Word documents puts pressure on them to
use Microsoft software and helps to deny them any other choice. In
effect, you become a buttress of the Microsoft monopoly. This
pressure is a major obstacle to the broader adoption of free software.
Would you please reconsider the use of Word format for communication
with other people?

See here for more about this issue.