You can create custom fields that will allow you to capture data from your users when they register for events, add hours, answer surveys, etc. Alternatively, there is also an option to create a custom field that only administrators have access to called "Administrative Fields".
Creating Administrative Fields
To create an admin field, you will head to your group dashboard > Customize > Users > select the administrative Fields tab. Once here, you can create your admin field by dragging and dropping the desired field and then adding your own label and description:
Accessing Administrative Fields
After creating your fields, you will be able to update the information for each user by going to Users > Manage users > Configure Layout. Please note that your admin fields will be recognizable by the "(Admin)" next to the title. After finding the field and applying it to your manage grid, you will be able to update the information for your users as shown here:
In addition, you can update the admin fields for a user by accessing their User Details and then going to the Administrative Fields tab: