“Apparently the latest directive . . . '

Actually, it's pointless when folk make this sort of post without providing a link to a source. Chinese is fine.

If you must have international roaming, ask them about the specific plan before signing up. Mine does not for sure. They explicitly said it's because mine is prepaid. Trying to enable it online also got rejected with 'plan not supported' error.

They xerox your passport, take your photo. The whole thing took an hour for me. That was 2-3 years ago.

I can't comment on current Telecom policies, but for both Mobile and Unicom, changing from one prepaid plan to another is extremely easy.

Is there a way to check what kind of plan I'm on? I remember signing up in Shanghai and they told me locally (within Shanghai region), I get X amount of data, but if I go to other cities (Beijing, Shenzhen, Chengdu for example), I have a smaller quota.

My Chinese isn't great so it would be nice if there are mobile tools that I can check with? I'm on China Unicom.

There is some sort of app, as well as a website, that my wife uses to manage her account at Unicom. But it's only in Chinese.

CM similarly has an app and website that'll provide this information, and you can also send an SMS to 10086 asking for your balance and other account information. In Chinese, though. Should be a code you can SMS, too, though the response will be in Chinese of course.

You should log onto your carrier's website to check your plan details. As of 2018, data roaming is now history so all your local data can now be used nationally.