There are three types of personal information which any user can update via Self service. 

To update personal details, using the left hand menu go to:

Self service -> My details

Here, you can change the following:

1. Personal details
2. Bank Details
3. Emergency Contact Details. 

If you wish to amend what fields are changeable on the 'Personal details' page then go to:

Administration -> Company -> Settings -> Company settings

Then go to the 'Self service' section:

Once there simply tick the checkboxes for fields you want to be changeable within self-service and untick those that you don't.

Please note: Whilst updating this information does not require approval, these updates will generate a notification to your HR department or Line Manager (dependent on how your Natural HR system is set up), notifying them of the change.