Thanks for joining the thread and following the suggestions above, @DebsTax2015.

I'd like to share some additional troubleshooting steps to assist you in attaching your PDF files to invoices or estimates in QuickBooks.

As previously mentioned, QuickBooks Desktop doesn't have a file size limit for attachments. Although, it's important to ensure that you have sufficient space on your local system to store the attached documents.

If you're trying to attach a document in QuickBooks and are unable to, the issue may be with the company file name. Attachments might not function properly if there are spaces or periods before the ".qbw" file extension, or if there are special characters within the file name.

The issue can normally be resolved by renaming the company file. To do this, follow the steps below:
 

1. Start by logging out of QuickBooks. Click on File in the top-left corner and select Close Company/Logoff.

2. Locate your company file. Click on the File Explorer icon located near the bottom-left corner of your Start bar.

3. In File Explorer, click on This PC on the left side. Find your company's main folder, typically named after your company and listed under the I:/ drive. If needed, hover over folder names to identify the one on the I:/ drive.

4. Open your company's folder by double-clicking on it. If your company has multiple users or numerous documents, you might need to search around to find the specific company file you want to modify. You can manually search or use the search bar in the top-right corner. If you use the search bar, typing "*.qbw" and pressing Enter will display all QuickBooks company files.

5. Now, edit the file name by clicking on the file and then pressing the F2 key on your keyboard. This will enable you to modify the file name.

6. Edit the company name to remove any extra spaces, periods, or special characters. After making the changes, press Enter or click elsewhere to save them.

7. Reopen QuickBooks. You should be directed to the No Company Open screen. Click on Edit List on the right-hand side.

8. In the new window, locate the row with the old company file. Click on the blank section under the far-left Hide column. A checkmark should appear. Once you've confirmed this company file is checked, select OK.
9. Click the Open or Restore an Existing Company File button near the bottom of the No Company Open screen.
10. Select Open a company file, then click Next. In the following pop-up, you will be asked to select your file from its location on the computer. It should open in the location where the file has been kept. Click on the file once and select Open.

Once the company file opens, double-check that you can now attach documents. You should be all set!
 

For more information on frequently asked questions and recommended troubleshooting for QuickBooks Document Center issues, you can refer to this article: FAQs and Troubleshoot Common Issues in QuickBooks Document Center.