Which types of fields can be added to a form?

The ability to add custom fields to a form in Marketo is a significant feature that allows marketers to capture specific information tailored to their needs. Custom fields are those fields that an organization defines based on its unique requirements—for example, fields that pertain to a particular product interest or demographic information that's not included in the standard set of fields.

When creating a form, you can incorporate all custom fields available in the database, which offers flexibility and adaptability in data collection strategies. This means that marketers have the freedom to setup forms in a way that aligns closely with their lead capture goals, facilitating better lead segmentation and engagement.

This capability distinguishes the option of "all custom fields" as the correct answer. It empowers marketers to go beyond a limited set of predefined data and ensure their forms can adequately support varied marketing and sales initiatives.