The Mundane Potion in Minecraft was a precursor to the Potion of Weakness, and there are many different ways to make one. However, it is no longer used in that way, or in any way for that matter, so the main reason to know how to make a Mundane Potion in Minecraft is so that you don't have to make one.

These are the materials you need if you want to make an everyday drink:

You will also need one of these ingredients:

To make a Mundane Potion, you will first need to craft a Crafting Table, and then a Brewing Stand. You will also need to craft or find a glass bottle, fill it with water, and then find or craft one of seven ingredients that you can use to make a Mundane Potion.