I'm here to help you manually add your credit card statements, @qqrenee. You can do this by entering each transaction manually as an expense. Let me walk you through the process step-by-step.
Before continuing, since you've mentioned that you can't find the upload option on your bank transaction page, you can try to check in the drop down menu next to Link account:
- Go to Transactions menu, then click Bank Transactions.
- Select the drop down menu next to Link Account.
- Click Upload from file.

Alternatively, you can access it through the Gear icon. Here's how:
- Go to the Gear icon.
- Under Tools column, select Import Data.
- Click the dropdown menu in the Select record type, then choose Bank Data, and Import.
- Proceed in uploading your bank statements.
If you're unable to upload the bank statements, you can alternatively add the credit card statements manually by following these steps:
- Click + New.
- Under the Vendors column, select Expense.
- Input the Payee name and choose the Credit Card used for the transaction in the Payment Account dropdown.
- In the Payment Method, choose the Credit Card type.
- Complete the remaining required fields.
- Once done, hit Save and Close.
I've provided a screenshot for your visual reference:

For more information, refer to this article: Enter and manage expenses in QuickBooks Online.
Moreover, when entering a transaction in QBO, it's important to categorize it properly to ensure the transactions are allocated to the right accounts.
Furthermore, it is advisable to reconcile your accounts monthly to ensure they consistently align with your bank and credit card statements.
Additionally, I'd like to introduce our QuickBooks Live Bookkeeping Assisted to assist you in organizing your finances seamlessly and efficiently. We have experts who will work directly with you to categorize transactions, reconcile accounts, and customized reports. This service will save your time so you can focus more on growing your business.
If you still have questions regarding uploading your credit card statements, feel free reply to this post. I'll be here to help you!