How do i unlock selections so i can type more on a document?

[Em-J]

every time i try to alter the text on all of my word documents a message
comes up in the bar at the bottom saying "This modification is not allowed
because the selection is locked". I'd like to know how to fix this.

 

[Suzanne S. Barnhill]

Either your copy of Word is a trial version that has expired or you have
failed to activate it.