You can view and edit company account details under the Settings section of the Web Portal >select Settings cog from the top menu bar > Choose Company Profile > Company Details > once you have updated your Company information select Save.

Handy Hint: If you have created Invoices, Quotes, forms etc. and you would like them to have your newest company information reflected, you can simply re-save or regenerate them and the new information you have just added will update for you.