Composed by Sri Adi Shankaracharya. Aparadha Kshamapana stotram is usually recited after a recital or after the completion of Puja. Its like asking for forgiveness from Goddess for various mistakes that one might have done during the recital/puja including (but not limited to) mispronounciations of mantra, omissions of bindu visargas etc, not showing proper mudras etc.