Disable username field from s2member registration form

Hi,

I have used s2 member stripe pro form for registration. please
go through the below link to view the form:

http://orderotk.wpengine.com/apply/

My client would like to hide username field from
registration form. I got a code from old s2 member forum, please go through the
link:

http://www.primothemes.com/forums/viewtopic.php?f=36&t=14806&p=33812#p33812

But unfortunately the code is not working properly. It will be great if you could share some guidance
to set the feature. Thank you

Is there anyone for help?

Try this: https://s2member.com/kb-article/using-the-e-mail-address-as-the-username/