How is the answer to Istikhara [prayer for guidance] determined if the job offer was made before performing the Istikhara prayer and no application for the job had been submitted? And is it necessary to consult someone, or will the answer become apparent after commencing the work?

The answer to Istikhara (prayer for guidance) is according to the supplication itself: if the matter is good, Allah will facilitate it, and if it is evil, He will avert it. The preponderant opinion is that a person should proceed with the matter after performing Istikhara, and should not abandon it unless Allah diverts him from it.