This is the 347th most frequent Spanish word.
esté
"Esté" is the present subjunctive form of the verb "estar," meaning "to be."
In this sentence, 'esté' is the subjunctive form of the verb 'estar', used here because the sentence expresses a desire or wish regarding someone's health.
Espero que esté bien de salud.
I hope that they are in good health.
Here, 'esté' is in the subjunctive mood, reflecting the necessity for the report to be in a certain state (finished) as part of an expressed importance.
Es importante que el informe esté terminado a tiempo.
It's important that the report is finished on time.
In this case, 'esté' is used in a situation of doubt, which triggers the subjunctive mood.