Hello there, JohnFish.

You can locate the Gear icon at the upper right corner next to the Magnifying icon. You can refer to the screenshot below. You can also check this site for some video tutorials for QuickBooks Online.

You can also follow these steps on how to delete or replace your company logo:

1. From the Gear icon, select the Account and Settings.
2. On the Company tab, select the Company name section.
3. Click on the company logo. You can delete or replace it on the pop-up.
4. Select Save.

Also, these are the steps if you're trying to delete or replace the logo in the sales forms:

1. From the Gear icon, select Custom Form Styles.
2. Locate the form. Click on Edit under Action column.
3. Select the Design tab. Select the Make logo edits.
4. Click on the Plus icon at the bottom left of the logo.
5. Make the change on the pop-up. Click Save, then Done.

You can read this guide about customizing sales forms.

Comment below if you need additional help. I'm here to guide you.