How to pass the parameter to the Oracle API

Help
1

When i am Trying to execute the below code it is getting the error
“String constants should end with Double quote”
can you please help on this.

“BEGIN
fnd_user_pkg.UpdateUser (
x_user_name =>'”+v_user_name+“',
x_owner => null,
x_email_address =>‘testuser@taz.com’,
);
End;”