Registration page

hey, I have xwiki for corporate documentation, where users log in using LDAP, but I would like to add the option to register via the register button but I don’t know where. I searched and found that I need to change the settings for " any global user cam request to join but an admin must accept"
in Admin>> User
but I don’t have that option
where can i change it?
this is how it should be
3
and for me it looks like this