How do i get my bank details attached to my invoice

It's great to see you here, @jorr-groundworks,

To attach files on transactions, use the Attachment feature for it. Here's how to attach files in the Attachments page:

1. Go to the Gear icon and select Attachments.
2. Click the Attachments icon to open the files.
3. Hold the CTRL button on your keyboard and select the items to upload.
4. Once everything is selected, release the CTRL button and hit Open.
   

To attach documents on transactions:

1. Open any income or expense transactions in QBO.
2. At the bottom click the Attachments icon.
3. Do steps 3 and 4 from the instruction above.
   

Get to know more about this Attachments feature by checking out this article: Attachments in QuickBooks Online

If you need further help with this topic, let me know in the comment. I'm always here to help you. Have a wonderful day!