You can always change and update your General Account Details from with your settings panel.
HOW TO UPDATE YOUR GENERAL ACCOUNT DETAILS
To update your account details go to the ⚙️ Settings tab.
Here click on Account Details which will display your current details on the right hand side.
Here you will be able to update your:
EU Vat Number
When you have finished updating simply click on the green ✔ Save button to save save your updated Account Details.
You are also able to change your Notification Message Preferences ( See here for more details on Notification Message Preferences )
Here you also get your API Settings for 3rd party integrations. ( See here for more details on API integrations )
You can also enter you Google Analytics Tracking Code to add Google Analytics capabilities. ( See here for more details on Google Analytics Integration )