We can customize the member registration form field from the admin side. The fields can be set as required or not required. (If you want to leave the field blank, it's optional)
The sort order- order in which the custom fields are displayed in the user side. Fields can also be specific.
When you select the 'Custom Fields' link it will display custom fields and screens. Just follow these steps from 1-4
1. Select 'Add Custom Fields'
2. The custom fields will appear in the adding screen.
3. You will receive a 'Custom Fields Added Successfully' message.
4.The screen will display the newly added custom fields.
You can edit/delete the custom fields only if it is empty. This means that the custom fields contain no data. If the custom fields contain data a 'Full Custom Field' message is displayed.
Custom Fields Editing
To edit a custom field follow the steps from 1 to 5
1. Click on the icon 
2. You will get access to "Custom Fields Editing Screen".
3. Enter the details in the corresponding boxes.
4. Click on "Update" button once you entered all the details.
5. You will receive a "Custom Field Updated Successfully" message
and you will be redirected to custom field listing screen.
Custom Fields Deleting
To delete a custom field follow the steps from 1 to 4
1. Click on the icon 
2. You will get a delete confirmation message.
3. Deleting does not remove the record from the database permanently.
4. You can undelete the same record by clicking on the same icon.
Editing the Custom Field Data
Editing the custom field data can be done if you follow steps 1 to 7
1. Click on the icon 
2. Displays the "Custom Field Data" Editing screen.
3. Select the user from the drop menu.
4. Custom field data of that particular user is displayed.
5. Make the necessary changes.
6. Click on the "Update" button to finish editing.
7. You will get "Custom Field Data Updated Successfully" message.