CMS Desk > On-line marketing > Contacts > Accounts > Account edit:
Here you can enter custom fields values of the current account, as defined in Site manager -> Development -> System tables -> Edit () Contact management - Account on the Fields tab. When you have entered the values, click Save to save the fields.
Help URL: http://devnet.kentico.com/docs/7_0/contexthelp/index.html?onlinemarketing_account_customfields.htm