I would like to upgrade my Subscription?

Hello there, @xhobisatp-gmail-.

Upgrading your subscription comes with easy steps. I'd be glad to show you on how to get this done.

You can have the option to upgrade your subscription from the Billing and Subscription page.

To do that:

1. Click on the Gear icon and select on Account and Settings. 
2. Refer to the Billing & Subscription tab.
3. In the QuickBooks Online section, select Upgrade your plan. If you don't see it, you’re already using the plan with the most features. 
4. Choose the plan you want, and press on Upgrade.
5. Confirm your payment information and select Save.

However, if you don't have the option to upgrade on that page, you can click on any of the transaction choices on the + New button that has an arrow on it. This will lead you to the upgrade page.

I've got steps and a scenario here for you. (The scenario upgrading from Simple Start to Essentials)

1. Hit on the New button at the left pane.
2. Select upgrade arrow beside Bills.
3. On the QuickBooks versions page, choose Essentials and tick Upgrade button.
4. From the subscription page, verify your payment details then put a check-mark on the authorization box.
5. Press on Change Plan.

I've outlined these steps below for your reference:

Let me know if you have any other questions on this. I'll make sure you're taken care of. Have a wonderful day!