The nominal code is how the system identifies what the transaction was for and where to allocate it i.e. travel expenses, wages, mileage etc.
You can start typing the description, such as “tr” then “travel” will appear. Alternatively, you can press the "space bar" and the full list of codes will appear. If however you cannot locate the type of transaction by typing it into the nominal code box, you can see a full list of codes available to use by clicking on the “Settings” tab and selecting “Chart of Accounts”.