it is not visible but default content type is their and can be access via site collection named /sites/contentTypeHub
.
But here is one issue. only the original Office 365 account creator has access to the site collection. Accessing it with another user will get you an access denied error message even if you are a global administrator.
fix: Unfortunately, you cannot fix this yourself from the tenant administration page because this site collection does not show up on the list. This means you need to get the person who created the original Office 365 account to go to this site collection and add you as a site collection administrator. It’s easy to fix but it requires you to involve whomever set up the account to begin with.
http://dotnetmafia.sys-con.com/node/2172946/mobile