Navigate to Tools > Options > App Settings > Inventory.

The Margins/Markup settings allow you to establish default profit margins and markup percentages for your inventory items, helping maintain consistent pricing and profitability across your inventory.

Within the Inventory Options section, the Restrict Sales to Available Inventory Items Only setting controls whether inventory quantities are validated when items are added to an invoice.

When this option is enabled, users can only add inventory items to an invoice if sufficient quantity is available on hand. This helps maintain accurate inventory levels and prevents overselling.

When this option is disabled, users can sell any quantity of an inventory item regardless of the available stock. While this provides greater flexibility, it may result in inaccurate inventory counts and can negatively impact inventory tracking and reporting accuracy.