Why doesn't my logo show on my printed invoice?

The invoice takes your logo from Settings → Web Settings → General Settings, under Primary Logo. Check that:

1. A logo is uploaded in Original Version (or the Light or Dark version) and you clicked Submit. If the box says Using default, no logo is set.
2. Your active invoice template includes the store logo field. The built-in Classic and Compact / Receipt templates do, but Modern does not, so switch template or click Edit on it and insert the store_logo chip. A custom template needs the store_logo chip inserted from the editor.

Then click Preview on Settings → Store Settings → Invoice Templates to check it before printing again.