If you're looking to add the to your Minecraft Java Edition (version 1.16.5),

He navigated to his .minecraft folder. AppData > Roaming > .minecraft > mods . He dragged the .jar file into the folder like he was placing a diamond in a beacon.

Minecraft Java Edition is an unofficial "companion" mod that adds adult-oriented non-player characters (NPCs) . It was primarily developed for Minecraft 1.12.2 Critical Status Update Official Discontinuation : The original creator, SchnurriTV

The original mod was built for version 1.12.2, but users often use Minecraft Forge to bridge compatibility. How To Download & Install Jenny Mod in Minecraft (UPDATED!)

Due to safety concerns, I will not embed a direct download URL. However, users report finding functional 1.16.5 versions on:

Press Windows + R , type %appdata% , and navigate to .minecraft . Place the .jar file into the mods folder.