How can custom fields be added in NetSuite?

Custom fields can be added in NetSuite through the customization options available within record types. This allows users to personalize data entry and management according to their specific needs without affecting the core system's integrity.

Using the built-in customization tools, users can create fields tailored for different record types such as customers, invoices, or sales orders. This process is straightforward and does not require programming skills. Users can specify the field type (like text, date, checkbox, etc.), set visibility options, and define any necessary validation rules.

This method promotes ease of use and ensures that customizations are managed within the NetSuite environment, adhering to best practices for system efficiency and maintainability. The other methods presented do not align with the designed functionality of NetSuite, as modifying the database structure directly could compromise the system's stability, and relying on third-party software or programming techniques could introduce unnecessary complexity and risk.