Explanation

Does she write an essay means کیا وہ ایک مضمون لکھتی ہے

Is an essay written by her means کیا ایک مضمون اس سے لکھا جاتا ہے

Present Indefinite Tense

Active Voice: Subject + Verb + Object

Passive Voice: Object + is/am/are+ third form of a verb + by + subject.