There is the free trial, which caps you at level 60 and its associated story and content.

There is the Starter Edition, which removes the free trial restrictions (but doesn't change level cap), gives you your first subscription and costs almost the same as a subscription.

There is the Endwalker expansion, which gives you access to all the expansions up to level 90.

There is the Complete Edition, which is the same as buying Starter + Endwalker.

Then there is a monthly subscription, which is what you need to setup 1 month after buying the game if you want to continue playing.

You most likely bought the Starter Edition. If you bought anything else, such as Endwalker, then you need to register the code to your account so that the game will know you can level to 90.