I'm not able to customize Invoice format

I can help you sort things by customizing your invoices in QuickBooks Online (QBO), @abconsafetyconsu. 

To begin with, we can change your logo by importing a picture saved from your computer to create an invoice. 

Here's how: 

1. Go to the +New icon.
2. Select Invoice.
3. On the page, click the Add logo at the top right part of the page.
4. Choose the file name from your computer and open it. 
5. The maximum file size of the logo is 1 MB. 

The logo will be set as default in your moving-forward transactions. 

After that, edit and find a font that will suit your preference in the right part of the invoice page. 

Here's how: 

1. On the Invoice page, click the Design drop-down.
2. Scroll to the bottom.
3. Under Font, choose a font that you want in the options.
4. Once done, select Save and close. 

Furthermore, you might want to check this article and learn how to send invoices over time as you work off an estimate in QuickBooks: Set up and send progress invoices in QuickBooks Online.

We are looking forward to helping you. Just leave a reply in the comment section if you require additional assistance managing your invoices. Stay safe.