You can include attribute elements on most forms. They are custom fields you add to a form. For example, you can include the Constituent Attributes element on the Profile Update Form to obtain t-shirt size information for constituents. Existing attributes integrate from Blackbaud CRM.
Note: If you know an attribute exists, but do not see it in Forms, check the Settings tab in Sites & settings to verify the attribute is available. For more information, see Attributes settings.
When you create the Profile Update Form and Allow only one per record is selected for the attribute category in Blackbaud CRM, the attribute appears as a drop-down field on the web page so users can select only one option. When this is not selected, each attribute appears with a checkbox beside it so users can select multiple options.