sqlplus connect <sys>/<pwd> grant execute on utl_file to <user> connect <user>/<pwd> DESC utl_file
then i get: ORA-24372: invalid object for describe
How can I access to UTL_FIL from other users in 11g xe? I already tried with public as well
The grant worked just fine. You can't DESC a package or procedure, which is why you're getting an error.
Documentation for UTL_FILE is here. It provides sample PL/SQL that shows you how to use the package.
A short code snippet that sums up its functionality is here.