HomeExemption Certificate ManagementExemption Certificate ManagementOverviewAPIMCPIntegration guidesECM (AvaTax) APICertCapture RESTful APIsModelsTransactionLineUserDefinedFieldModelUser Defined fields/Flex Fields at Transaction Line level.ParametersnameOptionalstringThe name of the user defined field.valueOptionalstringThe value of the user defined field.View Example