The Accounts tab defines default accounts used in various situations. Selecting all accounts is not mandatory, but without their configuration, certain functionalities will not work properly. It is important to define Sales Account, Receivables Account, VAT Account, and Manual payment Account. Defining other accounts is necessary when automatic matching of payments is used.
Account Settings
Sales Account - Default sales account for invoice lines if no other default sales account is defined for customer or product.
Receivables Account - Configuration needed for accounting transactions. If no other default accounts receivable account is defined for the customer, this account is used for payments in accounting transactions.
VAT Account - Necessary only if data is transferred to another accounting system where VAT needs to be separated before transfer.