How to show stats info on HUD?

These stats are there through a mod. More specifically Missing HUD 2.

You have to run the program you download at the same time as you are running Afterbirth, and then these stats will show up. They will always update to whatever your currents stats actually are. Some items aren't calculated for, things such as lump of coal give no visible result (since the damage is only added while your tear travels).

As of the new Afterbirth+ DLC, this functionality is built-in, meaning you do not need to download any third party tools like Missing HUD 2.

To turn on these stats, open the Options menu and turn on the "Found HUD" setting to activate this feature.

The Found HUD functions identically (as far as I can tell) to the Missing HUD 2 mod.