Hi,
sorry for late reply, it was late for us and our offices were closed
Can users during registration select user group (registered, author,...) and that based on selected value coresponding fields will appear (different fields for different user groups)?
Yes, you can create for example a select field with these options:
1|Registered
2|Author
3|Manager
and set following condition on this field:
Condition 1
Condition: equal
Field to compare: Custom Value
Custom Value: 2
Target Field: (leave empty)
Target Action: (not important)
Add to Usergroups: Author
Condition 2
Condition: equal
Field to compare: Custom Value
Custom Value: 3
Target Field: (leave empty)
Target Action: (not important)
Add to Usergroups: Manager
Registered usergroup is mandatory for all users because this is set in Joomla configuration at Users->User Manager->Options->New user Registration Group parameter
Now:
- if user choose "Registered" then he will be assigned to "Registered" usergroup
- if user choose "Author" then he will be assigned to "Registered" and "Author" usergroups
- if user choose "Manager" then he will be assigned to "Registered" and "Manager" usergroups
And is it possible if they select registered they can self activate account but if they select author I as admin must activate account?
No sorry this is not possible, to do this you need to develop a custom plugin, but this require PHP and Joomla devs Knowledge. here a docs with example plugin
https://www.easy-profile.com/docs/44-triggers.html