Sri Devi refers to Shakti, the Divine Mother. Word 'Khadga' means Sword, 'Mala' means Garland, Stotram means a hymn or song of praise. So the Khadgamala Stotram is a hymn sung in the praise of Divine Mother, which is said to bestow a protective garland of mystical weapons from the Devi from all sorts of Calamities upon those who recite it.
There are many types and levels of worship of the Devi(s) of the Sri Chakra. The Khadgamala is the simplest way. It is simply reciting the names of all the Devis of the Sri Chakra. It is an excellent rejuvenator of the body, mind and the soul.