Before you can store a pointer to a file in a BFILE column, you must first create a directory object.
The directory object represents the directory in the file system.
You create a directory object using the CREATE DIRECTORY statement.
To perform such a statement, you must have the CREATE ANY DIRECTORY database privilege.
CREATE OR REPLACE DIRECTORY SAMPLE_FILES_DIR AS 'C:\';
When you create a directory object you must ensure that
The actual directory exists in the file system.
The user account has read permission on the directories and files.