〜させてもらう／させていただく
To be allowed to do, to ask permission to do (humble)machine translation
FormationVerb causative form (〜させる) in the て-form + もらう／いただく
〜させてもらう combines the causative form with もらう, which you learned at N4: literally "to receive someone letting you do something," i.e. "to be allowed to do." The humble form させていただく is even more polite and very common at work: 説明させていただきます (allow me to explain).
This pattern grows out of 〜させてください (N4): while させてください is a direct request for permission, させてもらう・させていただく can be conjugated flexibly — 休ませてもらった (I was allowed to take time off), 使わせてもらえますか／使わせていただけませんか (may I use this?). The question form in the potential is the softest, most natural way to ask permission.
The core nuance: the action is your own, but you get to do it thanks to the other person's permission or goodwill, so the sentence sounds humble. Therefore use it only when there is genuinely an element of "asking permission"; for actions that are obviously your own business, plain wording is enough.
Examples
明日は休ませていただきたいのですが。
I would like to ask permission to take tomorrow off.
この写真を使わせてもらってもいいですか。
May I use this photo?
では、会議の予定を説明させていただきます。
Well then, allow me to explain the meeting schedule.