Harry Potter: Wizards Unite contains almost all of the goodies that you can find in the Potterverse. Chief among them are the Portkeys, which, in the books, allow you to transport from one location to the other.
Portkeys in this game allow you to go somewhere else, yet still to traverse your new location via AR, meaning you still walk around it in real life, with an open game or with Adventure Sync.
To get Portkeys you need Portmanteaus, and then beyond that, you need Silver Keys and Golden Keys. So how do you get them and what do they all do? Glad you asked:
Portmanteaus
Portmanteaus can best be thought off like the eggs in Pokemon GO, except that you collect them directly from the map. Look for what looks like a small building or chest with a pointy top. Pick it up whenever you see it and then you can begin unlocking it.
You can get either a 2km Portmanteau, a 5km Portmanteau, or a 10km Portmanteau. The longer the associated distance, the longer it takes to unlock, and the rarer the rewards (Foundables, Confoundables, Ingredients, etc) inside will be.
Being that this game is made by the same company as Pokemon GO, expect some sort of special Portmanteaus that can only be traded among friends to be added to the game at some point or another. These could be added as a special promotion for a new Potter movie or book, for instance, and can have their own unique distance, such as 7km.
It’s important to note that as of the initial release, Adventure Sync is not yet an option in this game, so you have to have the game open in order to have your steps counted for miles or kilometers. An update adding Adventure Sync should be coming very soon though, since the feature is already added to Pokemon GO.
An easy way to cheese your way through unlocking Portmanteaus is to ride a bike around your neighborhood at non-car speeds, or even better (for parents and older siblings), to stick your phone in your kid or sibling’s pocket (especially for little kids who take lots of short quick steps) so that your phone registers a gigantic amount of steps quickly. Of course, this will be much easier to pull off when you eventually have Adventure Sync.
Golden Keys and Silver Keys
These are analogous to the incubators in Pokemon GO. Use a key to unlock a Portmanteau and then you can begin walking the required distance for it to unlock. The Golden Key lasts forever; you can use it to unlock one Portmanteau after another, and it never goes away.
The silver one, on the other hand, goes away after unlocking a limited number of Portmanteaus. The recommended strategy is to use your golden key on the 2km Portmanteaus and your silver key on your 10km and 5km ones so that you can get the most mileage (literally) out of your silver keys.
Portkeys
Unlock a Portmanteau and it becomes a Portkey. Once you get a Portkey, it appears on the exploration map, so keep it close so that you can tap it.
Once you tap the Portkey, you’ll portal over to a new world for a temporary amount of time. Here, you’ll be able to explore a fictional world, but you’ll explore it as if you were using the AR function to explore the real world, so make sure you have some walking space where you place it, or you’ll risk tripping and falling over something.
Look around your new location to find all sorts of things to tap. You’ll find all sorts of Foundables, many of which won’t even require you to get rid of a Confoundable, because it’s already in a magical location. You’ll also find plenty of rare items, ingredients, potions, and more. Much of what you find in a Portkey is exclusive to the Portkey, which is what makes the Portkeys an important part of the gameplay.