Is there any official program in Ubuntu Software Center or some Official Tool that can remove metadata from documents (Generally LibreOffice Writer, PDF and if it's possible Images)?
User data can be viewed and cleared by going to File > Properties. Under the General tab you can click Reset to reset the general user data like total editing time and revision number. Also, uncheck the Apply user data checkbox on this screen. then click the Description and Custom Properties tabs and clear any data you don't want disseminated. On the Security tab, uncheck the Record changes checkbox if not already clear.
If you use the Versions feature, go to File > Versions and delete any older versions of the document that may be stored there.
Under Edit > Changes > Accept or reject, you can clear these if the recipient doesn't need them.
Just for Writer, under View > Hidden Paragraphs, check this feature to be sure all hidden paragraphs are visible.
Just for Calc, go to Format > Sheet and be sure there aren't any hidden sheets.