Thanks for posting in the Community forum, @tprservices.
Yes, you can change the size of your logo as long as it met the following requirements:
- a .gif, .bmp, .png, .jpg, .jpe, or .jpeg file
- smaller than 10 MB
- 24-bits or less in bit depth (or colour depth)
- square-shaped, since rectangles don’t work
- using the standard RGB colour space. Note: If your logo is CMKY-formatted, convert it into an RGB image using tools (such as Adobe Photoshop) before you upload it to QuickBooks Online.
For more detailed information about adding your logo on your invoice, check out this article: Add, customise, or remove logos on sales forms.
You can also try using Windows Paint and enlarging the logo in Windows Paint and saving it and then going back to QuickBooks Online and uploading the newly saved logo.
I'm always here for you if you need anything when adding a logo, just leave a comment below. Have a great day!