English Transliteration:
Allāhumma innī astakhīruka biʿilmika wa astaqdiruka biqudratika, wa asʾaluka min faḍlika (a)l-ʿaẓīm fainnaka taqdiru walā aqdiru wa taʿlamu wala aʿlamu wa anta ʿallāmu (a)l-ghuyūb. Allāhumma, in kunta taʿlamu anna hadha (a)l-amra [mention decision here] khayrun lī fī dīnī wa maʿāshī waʿāqibati amrī faqdurhu lī wa ya (a)s-sirhu lī thumma barik lī fīhi. Wa in kunta taʿlamu anna hadha (a)l-amra sharrun lī fī dīnī wa maʿāshī wa ʿāqibati amri faṣrifhu ʿannī wa (a)ṣrifni ʿanhu waqdir lī(ya) (a)l-khayra haythu kāna thumma arḍīnī bihi.
English Translation:
Dear God, I’m asking You for goodness through Your [Infinite] Knowledge, and I’m asking You for strength through Your Divine Ability, and I’m asking You from Your Infinite Grace. Because You’re completely able to do, while I simply cannot. You know everything, and I do not, and You know everything that’s unseen. Dear God, if You know that this decision [mention decision here] is good for me in terms of my religiosity, my worldly life, and afterlife, then decree it, facilitate it for me with ease, and bless me through it. But if You know that this has bad consequences on my religiosity, my worldly life, and afterlife, then get it away from me and get me away from it, and [instead of that] decree what’s better for me, whatever it may be, and make me content with it.
How
1) Make Intention for Istikhāra
2) Pray two rakaʿāt of voluntary prayer (any prayer outside the five obligatory ones) and recite any Surahs you’d like after Fatiha in each rakah as there are no Surahs specifed by The Prophet ﷺ.
3) Recite the duʿāʾ (prayer) of istikhāra in Arabic as recommended to us by the Prophet ﷺ once you say your salām for the prayer – and then explicitly state your need in any language you’d like.
If you don’t have it memorised, read it off a paper or your phone. If you can’t read Arabic, read the transliteration. No extra duʿāʾ afterwards is required.
Outcome
You will NOT necessarily see a dream/vision/sign/etc. Allāh ﷻ will place a bit of inclination in your heart towards going through with the action or not. You can also ask Allah for further guidance, blessing and firmness in the decision that you have already made through this duā.
If the decision affects more than one person, everyone involved should pray their own istikhāra.
Conclusion
Istikhāra is a natural process. Don’t expect anything otherworldly. All istikhāra ensures is that you have the blessings of Allāh backing your choice. There is no istikhāra for Ḥarām actions (I.e. Should I drink this alcohol?) or obligatory actions (i.e. Should I pray ʿĪshāʾ today?). Do not regret your decision afterwards as doing so would be to regret and doubt in Allāh’s guidance. Even if your decision “doesn’t work out” how you envisioned, know that it was better for you and that there are blessings in it even if you can’t see them yet.
This was shared in some part from ISTIKHĀRA: HOW & WHY.