させる covers both making someone do something and letting them — which reading applies depends on の particle and context. These cards cover the form and the two readings.
Also known ascausative form使役形shiekikeisaserumake someone do
行く→行かせる, 食べる→食べさせる, する→させる, 来る→来させる.
ははは こどもに へやを そうじさせます。
The mother makes her child clean the room.
Group I: あ-row + せる (行く→行かせる, 読む→読ませる). Group II: ます-stem + させる (食べる→食べさせる). Irregular: する→させる, 来る→来させる.
With an intransitive verb the person made to act takes を (子供を 行かせる); with a transitive verb they take に (子供に 本を 読ませる).
In the textbooksMinna II, lesson 48
Politely ask to be allowed to do something: causative て-form + ください.
すみませんが、はやく かえらせて ください。
Sorry, but please let me go home early.
The causative て-form + ください asks for permission to do something yourself (“please let me…”). More humble: 〜させて いただけませんか.
In the textbooksMinna II, lesson 48