param = QgsProcessingParameterString('my_param', 'My Parameter', defaultValue='default_value')
param.setMetadata({'widget': 'textEdit'})
param.setFlags(param.flags() | QgsProcessingParameterDefinition.FlagHidden)This example sets a flag for the input parameter to be hidden in the algorithm dialog. Overall, QgsProcessingParameterString is used to define string input parameters for processing algorithms in QGIS and can be customized with various metadata and flags.