[users] Help with File extesions

[John Miskell]

Help! Without boring you with my computer ignorance, I wonder if I can get an 
automatic file extension of "doc". If I forget to change written text that I 
attach to emails, others that use Microsoft or Mac programs can not open  
extension "odt". I can change my documents to "doc" but it is not automatic.  
Can I modify Open Office so it is automatic?
I would appreciate a response.
Thank you.
John Miskell