Improvising NPCs can be one of the biggest challenges you face in the middle of a session you are DMing. You are already balancing dozens of other thoughts and factors at play, that a simple “Hey DM, can I talk to a random person walking down the street?” can throw you for a loop! I made this printable prep sheet to help Dungeon Masters take a moment to prepare basic information like name, description, and what this NPC is thinking/doing so you can reference that and not worry about creating an entire person and history the moment a player creates that scenario.
Give this a try and see if having a reference sheet ready to go helps you keep the game running smoothly and taking away future stress for yourself!