TO FILL SOMEONE IN verb to inform (someone) fully; to give (s | Phrasal Verbs Idioms

TO FILL SOMEONE IN
verb
to inform (someone) fully; to give (someone) the details

Lisa missed the meeting where that was discussed: so someone will have to fill her in.
I didn't receive the information in the mail—could you fill me in?
Please fill in the new secretary about our rules.