〜てもらう
Have someone do something for youmachine translation
FormationRecipient は/が + person doing the favor に + verb て-form + もらう（いただく）
〜てもらう means HAVING someone do something for you, seen from the receiver's side: 先輩に作文を直してもらいました (I had my senior correct my essay). The subject is the receiver (usually me), and the person doing the favor takes the particle に.
〜てもらう often implies that you asked for the favor: 兄に自転車を修理してもらった sounds like "I asked my brother to fix it and he did". This is the main difference from 〜てくれる — there, the other person acts voluntarily. With superiors, use the humble form 〜ていただく: 先生に教えていただきました.
From this pattern comes the highly polite request 〜ていただけませんか in a later lesson. Also don't confuse it with the passive: 直される is "to get corrected" — neutral or unwelcome, while 直してもらう always carries gratitude.
Examples
私は先輩に作文を直してもらいました。
I had my senior correct my essay.
兄に自転車を修理してもらいました。
I had my older brother fix my bicycle.
道が分からなかったので、警官に教えてもらいました。
I didn't know the way, so I had a police officer show me.