You can create new account types when creating a new account.
Currently, the account types of all accounts cannot be edited once set, so when creating a new account be careful when choosing the account type.
Navigate to Settings > Accounting > Account codes menu.
Click on the Create new account code button.
Add the new Account name, VAT rate and tick the checkboxes to show in purchases or sales as appropriate. Click on the plus icon in green beside the Account type drop-down list.
You will then be able to enter a new name in the New account type field and select an appropriate category. The categories cannot be added to or edited in any way.
Hit the Save new account button to complete.