Users with ‘Admin’ permissions on the Company level Admin tool have the ability to create custom fields and apply them to configurable fieldsets for supported tools within Procore. See Create New Custom Fields.
Configurable fieldsets are groups of fields available in certain Procore tools that can be set to optional, required or hidden. For example, configurable fieldsets could allow Company Admins to require cost codes in Working Hours Register entries. See Create New Configurable Fieldsets.