It is possible to conduct istikhara for just a marriage proposal by giving 2 raqat Nafil prayers (Namaz). You should recite Surah kafiroon in the main raqat of the istikhara prayer and Surah Al-Ikhlas in the second raqat. Eventually, you need to go through the particular istikhara dua for marriage https://devin7grzh.dailyhitblog.com/36534398/methods-of-combating-household-insects-in-unaizah-an-overview