Standard fields are predefined fields that are included as standard within the Salesforce CRM application. Standard fields cannot be deleted but nonrequired standard fields can be removed from page layouts, whenever necessary.

With standard fields, you can customize visual elements that are associated with the field, such as field labels and field-level help as well as certain data definitions such as picklist values, the formatting of auto-number fields (used as unique identifiers for the records), and the setting of field history tracking. Some aspects, however—such as the field name—cannot be customized and some standard fields (such as Opportunity Probability) do not allow the changing of the field label.

Custom fields are unique to your business needs and can not only be added and amended, but also deleted. Creating custom fields allows you to store the information that is necessary for your organization.

Both standard and custom fields can be customized to include custom help text that helps users understand how to use the field.