Welcome to the Community space, @cityplumbingserv. We'll share information to help you add a logo to your sales forms inside QuickBooks Online (QBO).
When adding a logo to your sales forms, you'll need a template or a customized template. This way, it is easier to distinguish which template has the logo and is used for your invoices and estimates. See this page for further guidelines: Customize invoices, estimates, and sales receipts in QuickBooks Online.
If you already have an existing template, here's how you can add a logo:
Access your QuickBooks Online company.
On the top-right corner, click the Gear icon.
Under Your Company, select Custom form styles.
Find the template, then select Edit under the Action column.
Go to the Design tab, then select Add your unique logo.
Select the box with Add a logo +, then the + on the next window.
Locate and select the image you want to use.
Select Open. Once uploading is done, select Save, then Done.
We're open 24/7 if you need further assistance adding a logo to your invoices and sales forms inside QuickBooks. It'll be our pleasure to help you at again. Stay safe, and have a good one. Keep safe.