If you're wondering how to find the shotgun in Resident Evil 2 Remake and the Weapons Locker Key Card, we'll take you through it. You'll find the W-870 Shotgun in a weapons locker in the Safety Deposit Room on 1F of the RPD building, which becomes reachable pretty early on. The lockers there contain other items that you'll need to access from the terminal with the two missing keys—but the shotgun is the main item of interest in the early part of the game. It's in a weapons cabinet at the back of the Safety Deposit Room, opposite the entrance. You can't open it without the keycard.
Here's the room's location for reference:
You'll need to head to the Fire Escape on the far east side of the building, accessible from the first floor—you'll know you're there because it takes you outdoors. Take the staircase at the Fire Escape to the second floor, then walk through the corridor leading to the left until you find the Art Room on 2F. Enter. You'll find the Weapons Locker Key Card. Here's the location of the Art Room so you can't miss it:
Alternatively, if you haven't got the shotgun yet but do have the Spade Key, you can reach the Art Room through the locked door in the Waiting Room, accessible from the second floor of the main hall. The Weapons Locker Key Card looks like this:
From here, it's a simple matter of running back to the Safety Deposit Room and using the key card. You'll get the shotgun and some ammo for your trouble. Now you're ready to deploy some serious firepower in the Resident Evil 2 Remake.