When I email invoices they are no longer showing as a pdf. It is in a weird format.

They may be a need to update your Adobe Reader to the latest version, mignonbonino.

1. Open Adobe Reader in a separate window.
2. Click Help.
3. Select Adobe Reader.
4. Go to the Adobe Reader Downloads page. The web page automatically detects your OS and Reader version.
5. Choose Install Now.
6. Open the downloaded file and follow the rest of the on-screen instructions to finish the updating process.

Once your PDF viewer is updated, set it up as a default application to open PDF documents. 

You can check this article for more information: How to update, repair, or re-install Adobe Reader/Acrobat.

On the other hand, you can also check the setting in QuickBooks if there were changes made.

Here's how:

1. Click the Gear icon.
2. Select Account and settings.
3. Click Sales on the left pane.
4. Scroll down to select Online delivery edit, make sure to check the box for PDF Attached.
5. Click Save, then Done to save changes.

Let me know if you have other questions about emailing invoices in QuickBooks Online