I know that navigating the platform as a new user can be challenging, Spectre.
Before we proceed, could you please let me know exactly where you're attempting to upload your company details or which tab you're currently on? I want to make sure I provide you with the right solution.
When you create a new profile with a QuickBooks Online subscription, you'll have to enter your company details manually. There's no option to upload this information directly into the system.
To set up your company details, follow these steps:
- Head to the Gear icon, then select Account & Settings.
- In the Company section, you'll find options to enter your company information.
- Once you've finished entering the details, click Done.
Here's a sample screenshot for visual reference.

Since you mentioned that some tabs are missing while setting up your company in QuickBooks, I recommend logging out and then back into your account to refresh your session.
If you want to manage multiple companies, you'll need to set up a new plan for each one. QuickBooks Online requires a unique subscription for every company file.
You can easily access and manage all these subscriptions under a single Intuit account, which allows you to switch between companies without the hassle of multiple login credentials.
This thread will remain open if you need more clarification. We're always here to help.