Peel and chop the potatoes so they're generally the same size. Put on a trivet, add 1 cup of water and cover with the lid. Make sure that the vent is set on the SEALING position so that the pressure can build up once it's on.
Press on MANUAL or PRESSURE COOK, and set at 8 minutes on high. Allow the Instant Pot to come to pressure and cook.
As you wait for the potatoes to cook, in a small saucepan melt the butter and add the minced garlic and herbs to the butter and cook for 1-2 minutes on medium heat. Set aside, and let the flavors infuse.
Once it's done, quickly release the steam and carefully open the lid. The potatoes will be cooked and tender but not falling apart.
While the potatoes are still warm, mash them right away with a potato masher, potato rice, or even the back of a wooden spoon. Add butter, milk, herbs, salt, and butter, and mashed everything together until the mash is smooth.
Finally, mix in the melted butter along with the herbs and garlic. If you prefer not to add any herbs to your mash, then just take them out before stirring them in. Have a taste and adjust seasonings to your preference.