A subform is a reusable form component that can be used to add multiple field entries to any custom module record form. For example, you can add a subform to capture processor / hardware details in an asset workstation add/edit form.
To add a subform, you must first create a subform type, which serves as a blueprint that can be reused to create subforms in other forms.
To add a sub form type,
Go to Setup > Customization > Subform Types.
Click New SubForm Type.


Click Save. Once saved, you can start designing the subform.
Design your form by adding fields:
Click New Field.
Enter a Field Name and Field Key.
Select a Field Type from the following: Single-line, Numeric, Pick List, Date/Time, Email, Phone, Currency, Decimal, Percent, Web URL, Lookup.
For Single-line, Pick List, Email, and Phone field types, encryption is available.
You can add multiple fields to a subform type as shown below.

Use the
icon beside each field type to reorder the fields.
Use the
icon to edit the field.
Use the
icon to remove a field from the subform type.
Click Save.
From the list view, you can do the following actions:

Edit Sub Form Type
Click on the settings icon and select Edit.
Delete Sub Form Type
Click on the settings icon and select Delete.
View Sub Form
Click on a subform type to view the associated subforms and see which modules they are linked to.

Subform Types appear in the available Subform Types list within custom module templates. You can add them as a new section or as a new field to existing sections in the template.
Just drag and drop a Subform Type to create a subform.

Provide a Subform Name and an optional description.

Click Save.
The subform will be added to the custom module record form.
