You need to buy them.
Usually they come with Shimano brakes, because it is their invention, but for other brands you need to insure one of the provider, hub, disc, or wheelbuilder provide you with some.
There are two types of rings.
Inside lockring, you tighten with a cassette lockring tool. Usually for 12mm axles.
However, some front hub, need a cassette lockring tool that is thinner.
As the endcap may not leave enough room for some tools.
DT-Swiss 240, some Novatec have this issue.
Unfortunately I do not have experience with Bitex.
Outer lockring, you tighten with a BSA hub tool. Usually for 15 and 20mm axles. And for the unlucky 12mm axles above too.
In that case, you need to insure your frame provide clearance as it is thicker, and may interfere with the frame.