How do I remove the list of attachments when I push "show existing" at the bottom of an invoice. Thank You

Hello, mortonray12.

Do you mean removing some of the attachments in the list? If so, please follow these steps:

1. Click the Gear icon in the upper-right hand corner of QuickBooks.
2. Select Attachments.
3. Look for the attachment that you want to remove.
4. Click the drop-down list beside Download and click Delete. 
5. Click Yes to confirm. 

Here's an article that talks about QBO attachments for more details: Attachments In QuickBooks Online.

Let me know if you have follow-up questions. I'll be around to help you again.