Salat al-Istikhara is a two-rak'ah voluntary prayer followed by a specific dua, taught by the Prophet (peace be upon him) for any lawful matter a person is unsure about, just as he taught them a surah of the Qur'an. After the two rak'ahs one supplicates: 'Allahumma inni astakhiruka bi ilmika, wa astaqdiruka bi qudratika...' asking Allah, if the matter is good for one's religion, life, and outcome, to decree and ease it, and if harmful, to turn it and oneself away from it. Istikhara is not a request for a dream or a feeling; it is asking Allah to choose the good, after which one proceeds and trusts His decree. It differs from a general dua for guidance in that it is tied to a concrete choice one is weighing.
Informational, not a personal fatwa. Consult a qualified scholar for rulings on your situation.