How do i get meteor shards?

You can get meteor shards from both invading and exploring wildlands, they are a random drop (sometimes you will be lucky and loads of them and other times nothing).

meteor I's are found in low level wildlands, thats lvl3 and down.
meteor II's are found in low to medium level wildlands
meteor III's are found in medium to high level wildlands

Sometimes you can simply have a bad luck streak where you almost get no meteors, and sometimes you get loads of them