Anonymous / FTP users are allowed to access the FTP. Suppose if there is a user named as JOE then how can I allow him to access the FTP?
Not sure why you chose vsftpd, as the documentation is notoriously lacking/distributed. However, to answer your question - the simplest method of allowing registered user access is through enabling local users:
There are other options, dependent on your needs, such as storing users in a database engine like MySQL. For more pertinent information, please check the following pages:
Assuming you meant you compiled vsftpd when you said "I made my own", then this information should apply. Let us know if this is an incorrect assumption or if the info provided doesn't assist.