Good day to you, @cassandra-vanroo.

Let me share with you some insights on why you’re unable to see apps in the Apps tab. It could be your region is one of the QuickBooks Online (QBO) international versions that doesn’t support app integration for now.

Rest assured, our engineering team is currently working on the app integration for the international version of QBO. While we don’t have a specific time frame as to when this will roll out, I recommend checking our QuickBooks Blog page regularly. This way. you'll stay updated on any news and releases in QuickBooks.

You can also check our QuickBooks Apps store and browse for an app from there. However, it would depend on your region for the availability of the apps.

In addition to this, I’d suggest checking out our Help articles page. There, you can browse some useful articles that serve as your future reference for your future tasks. 

Let me know if you other concerns or questions about your QBO account. I’ll be around to help you out anytime.

@cassandra-vanroo 

What kind of app do you seek? We may recommend some apps to explore.

I am looking for either an app or a plug-in for to add Crypto Currency and another for a trading options

We have to find yet any crypto currency or brokerage app supporting QB. Explore Mint instead. It is another product for personal finance.  It is able to track Bitcoin.