@David, you can not remove username field it is one of the required field used many places. However Birthdate and Gender is not which can be removed

https://www.opensource-socialnetwork.org/component/view/3644/remove-genders
https://www.opensource-socialnetwork.org/component/view/3645/remove-birthdate

The other way is to remove username is removing from signup but at backend a random username is generated for the user instead. If you wish this you can contact us using contact form for a component but note that the username will be still exists in system as a random username.

I've found ~/actions/administrator/user/add.php
and ~/actions/user/register.php
but I'm not confident that editing just those 2 would do what I want.

I've looked and found only this 8 year old thread.
Email address as username and password would be enough for my people.
It's beyond me to edit register action + OssnUser class.
Is succinct comprehensive help available? Paid?

Syed Arsalan Hussain Shah, would you please explain in detail:

Where are the files?
What do I look for?

thanks,
Blaine.

Yes, would you please explain in detail here! Thank you in advance.

@Syed Arsalan Hussain Shah can you explain in detail please?

You have to edit register action + OssnUser class.