By default, you cannot pause in Elden Ring, but due to what I can only assume is an oversight, there's actually a secret way you can pause in the game! It's not too useful, you're not gonna cheese anything with it. But if you wanna guarantee that you don't die while you go to the restroom or something, you can!

1. Step 1: Open Your Menu
   
   
2. Step 2: Choose "Inventory"
   
   
3. Step 3: Press the "Back" button, or whatever opens the "Help" menu, listed at the bottom.
   
   
4. Final Step: Select "Menu Explanation"
   

Since this pop up is considered a "tutorial" the game will fully pause to let you read this information. The game is now fully paused! Very useful if you need to tab out of the game, go to the restroom, or whatever else! And that's all :D