You have to browse to https://developer.here.com and create an account.
Once your account is created you can register for a plan: https://developer.here.com/get-started
When selecting your plan you'll get an appid and appcode that can be used in the app.
The free plan should be more than enough for basic usage of the HERE maps app.
I believe it loads tiles directly from the here api, although for a fee a believe you can download them and host them in your own app. (My car satnav uses here maps on an SD card (dont get me started!))
The concise answer is probably "not without $$$$"