Of the eight mātṛkās that surround each of the three major cities of the Kathmandu Valley (Kathmandu, Bhaktapur and Patan), Indrāyaṇī specifically is related to the Vedic deity Indra. She emanated from the body of Indra.
In the Kaula, Śākta and Tantra tradition, she is the consort of Kapāla Bhairava. Externally, Indra is the supreme king of multiple heavens. And his wife Indrāyaṇī, therefore, represents extreme sāmsāric happiness.
Astrologically, Indrāyaṇī is related to Venus. Indrāyaṇī presides over material happiness just like Venus. Those who want to start a happy marriage life or create stability in their marriage can worship Indrāyaṇī. Especially, men who desire a beautiful, feminine and devoted woman in their lives can achieve so by worshiping Indrāyaṇī.
Additionally, worshipping Indrāyaṇī can help men develop qualities associated with Venus such as knowledge of aesthetics and arts, development of skills in arts such as dance and music, capacity to engage in hankering-less enjoyment of the five senses, diplomacy, interpersonal intelligence, and ability to understand women.