"Shareholder wants to contribute on 401-K for $8000"

Is this for 2023 planning or for 2022 filing? For S Corp or personal? It's a bit late for 2022. Or, this is that same client you are catching up for 2022 payroll?

"and then Sch E what amount is going to be there? Box1 or Box3&5."

Sched E for 1040 or for 1120S? I'm curious for what part a 401(k) plays with which Sched E for that employment. I don't think I've ever been asked to link the data.