Question

How do I get Zamazenta in Pokémon Sword?

Answer 1

Zamazenta is exclusive to Shield. You can catch Zacian after completing the Sordward and Shielbert story in the postgame, but without trading, you cannot capture Zamazenta.

There were several events to obtain Zamazenta in Sword that have since passed; you may find these here.

Answer 2

You can link trade with a friend, trade via the GTS, or transfer it from Shield to Sword.

Hope this helps!!! :)

Answer 3

As of current, there is no way to get Zamazenta in Sword or Zacian in Shield. There were previous events where you were able to obtain it, however those have long passed. You're best bet is to trade with someone or use the GTS in Pokemon Home on mobile.