Greetings, @ehabab92.

I'd be delighted to help walk you through updating your payment method in QuickBooks Online.

Here's how: 

1. Click the Gear icon.
2. Select All Lists.
3. In  the Lists page, select Payment Methods.
4. Click New in  the Payment Methods page.
5. Enter  a name for the new payment method.
6. Check the This is a credit card box.
7. Click Save.

If you're referring to the payment method of your QuickBooks Online subscription, here's how:

1. Go to the Gear Icon.
2. Choose Account and Settings.
3. Select Billing & Subscription.
4. Enter the credit card information. 
5. Make sure to verify the billing address in QuickBooks Online is the same billing address on the credit card statement.
6. Click Save Changes.

On the other hand, if you encounter error while performing the update on your end, let's perform the following basic troubleshooting steps:

• Login to your QuickBooks Online account using an incognito or private browser. Kindly use either of the following shortcut keys:
  • Google Chrome, press CTRL  + Shift + N
  • Mozilla Firefox: press CTRL  + Shift + P
  • Internet Explorer: press CTRL  + Shift + P
  • Safari: press Command + Shift + N
• If you’re able to able to access your account and edit your payment method successfully, you may want to clear browsing history of your regular web browser.
• You can also use the Browser Health Checkup Tool to check any issues with your browser’s health and its compatibility with QuickBooks Online.

For additional insights, you may check out these articles:

• Change a vendor payment method
• Accept credit card payments using GoPayment

That should do it! Fill me in if you have other questions about updating your account's payment method. I’m always here to help.