Devi Aparadha Kshamapana Stotram iswas composed by Adi ShankaracharyaAdi Shankaracharya.It is usually customary to recite thisthe stotram after the completion of a Chandi Patha recital or after the completion of any Devi Puja.
It is like asking for forgiveness from Mother Goddess for the various offences(like not uttering Mantras correctly,not showing Mudras properly and even for generalor even general offences) one might have committed during the recital/puja(or otherwise).
The theme of this Storam is of total surrender to Mother Goddess and asking Her for forgiveness. Just like a mother never abandons her son ,no matter how many mistakes he might have committed,similarly this stotram asks Goddess to protect & forgive us like Her son.
The benefits of reciting(honestly) the stotram is obviously getting forgiven by Mother Goddess of the offences and sins one has committed.
The Stotram has 12 verses in all ,few are given below(with meaning).
A similar Aparadha Kshamapana Stotram dedicated to Lord Shiva is this
न मत्रं नो यन्त्रं तदपि च न जाने स्तुतिमहो न चाह्वानं ध्यानं तदपि च न जाने स्तुतिकथाः । न जाने मुद्रास्ते तदपि च न जाने विलपनं परं जाने मातस्त्वदनुसरणं क्लेशहरणम् ॥१॥
(O mother neither i know your Mantra,our Yantra,your Stuti,your Dhyanam,or even your Mudras.Not even i know how to cry for you.However, one thing I know (for certain); By following You (somehow through rememberance however imperfectly) will take away all my Afflictions (from my Mind),
नाराधितासि विधिना विविधोपचारैः किं रुक्षचिन्तनपरैर्न कृतं वचोभिः । श्यामे त्वमेव यदि किञ्चन मय्यनाथे धत्से कृपामुचितमम्ब परं तवैव ॥९॥
(O Mother) I have not worshipped You as prescribed by tradition with various rituals, (On the other hand) What rough thoughts did my mind not think and my speech utter? O Shyama, inspite of this, if You indeed, to a little extent, to this orphan ... ... have extended Your Grace, O Supreme Mother, It indeed only becomes You (i.e. is possible for You),
आपत्सु मग्नः स्मरणं त्वदीयं करोमि दुर्गे करुणार्णवेशि । नैतच्छठत्वं मम भावयेथाः क्षुधातृषार्ता जननीं स्मरन्ति ॥१०॥
(O Mother) I have sunk in Misfortunes and therefore remembering You now (which I never did before), O Mother Durga, (You Who are) an Ocean of Compassion, ... ... (Therefore) do not think of me as false (and my invocation as pretence), (Because) When children are afflicted with Hunger and Thirst, they naturally remember their Mother (only),
मत्समः पातकी नास्ति पापघ्नी त्वत्समा न हि । एवं ज्ञात्वा महादेवि यथायोग्यं तथा कुरु ॥१२॥
(O Mother) There is no one as Fallen like me, and there is no one as Uplifting ( by removing Sins ) like You, Considering thus, O Mahadevi, Please do whatever is proper (to save me).