Where do I register my Activation Code for Heavensward?

Hello again,

I verify Japanese Page that allow player to submit the Activation Code.

I couldn't use the code what I obtain from NA Square Enix page,

Do I have to wait for English Site will be Open?

You need to use the code on the NA preorder site, https://preorder.na.finalfantasyxiv.com/na if you bought an NA version. The NA one has been open since pre-orders started. You may need to use a VPN if it's redirecting you to another one.

EDIT: Having reread this, I see "I couldn't use the code that I obtained from the NA Square Enix page" so maybe you mean the early access code you got from the preorder site? You can't use those until June 17th or so.

If you on Playstation you will need to wait till you get the "GO" mail from SE that tells you that the code will be accepted on PSN Store.

I've ordered the EU PC version. In the e-mail I've received with the code it stated that I will receive a second e-mail. Once I get the second e-mail, then I can use the code.

This is a question that is more complicated than it needs to be because multiple codes are involved and the process depends on both platform and region.

But in short... the mogstation part of registration hasn't opened yet; you cannot register your final code (if you can even get one) on mogstation yet.

Now as for how to get to that point, see the above posts. Your location says Washington, so if you bought the US version on the US site: Use your code on the website included on the email. This will give you a second code. Save this second code somewhere, you can't do anything with it yet.