I have a client's invoice, and now I need to add additional entered expenses. There used to be an easy slide out tray - that's now gone. I can only create a "NEW" invoice

Thanks for explaining the issue with adding a billable expense to a client's invoice in QuickBooks Online (QBO), @scott40.

For an existing invoice, there's an extra step for the slide-out tray to appear and add the billable expense to the invoice. I can guide you through the steps to accomplish this.

You can follow these steps:

1. Open the existing invoice transaction. You can use the magnifying glass icon to locate it.
2. Click on the Manage tab.
3. From Suggestions, select Suggested transactions.
4. From the Filter drop-down list, choose Expenses transaction type.
5. Find the appropriate billable expense. Then, hit Add.
   
    

If you need to record invoice payments after this, I'm adding this article as a reference: Record an invoice payment.

If you have any other questions or updates about adding billable expenses to an invoice in QBO, feel free to click on the Reply button. Take care!

Thanks for the instructions, however I can't get past step one.

The +New dropdown doesn't have an option to select customers.

See screenshot.

But If I select +New > Invoice > Customer > The suggested transactions are listed already.

If I got to Clients > Customer Name > I don't see a manage tab.

So I tried +New > Invoice > Customer (suggested transactions come up without having to manage them) >leave without saving > Clients > Customer Name > Pulled up existing invoice > and the suggested transactions still aren't there.

Frustrating as I need to get this invoice out the door!

Let me clarify things for you, Scott40. We value your efforts and time spent performing the recommended procedures. Let's work side-by-side to ensure you can add the billable expense to your client's invoices.

You'll need to select the Invoice option after clicking the +New button on the left navigation panel. Let me lay out the steps for you:

1. From the +New button, choose Invoice under the Customers column.
   
2. On the Add customer dropdown select the specific customer with the specific billable expense.
   
3. Hit the Manage option and click the Suggestions tile.
4. Ensure it is enabled and everything is set up accordingly.
5. Click the Refresh button to reboot the system and recognize the changes.
   
6. Repeat Step 2, and then the Suggested transactions slide-out tray will display.
7. Choose Add on the billable expense, and enter the other necessary details.
8. Once everything is in place, click Save and close or Review and send.
   

For more info about adding billable expenses to your invoices, refer to this article: Enter billable expenses in QuickBooks Online. 

Reply to this post if you have additional concerns. Keep safe. 

HELLO - 

Those steps have been followed - allow suggested transactions has always been checked. 
The part missing is you say repeat step 2.  However that gives me a NEW invoice. 

As I said in my original post, I'm trying to add these to an EXISTING Invoice with NUMEROUS line items already.  It would take 30 minutes to redo them all.  And there's 30-40 billable expenses already entered, marked billable and matched to their bank transactions. I don't want to undo them all and start over.  That's crazy. 

So can expenses already entered, be added to an existing invoice? That's where the slide out with suggestions is NOT appearing.  It works fine if I want to start all over.

I called and I was told the feature 'must have been removed' which seemed crazy to me. 
So I continued to attempt and clicked on a location no support individual has mentioned and the person on the phone was surprised to see it. 

From the existing invoice, I clicked Manage and the show expenses box was checked - but no expenses were showing. 
So I clicked the blue text "Suggested Transactions" and THAT'S when the previously entered transactions showed up. Ya'll haven't mentioned clicking there, you simply said after checking the box, refresh, but that was always for a new invoice.   I lost hours with this change.  All support should know about this and update the support search results to address this change.  Currently when you search 'add existing expenses to an existing invoice', it's focused on expenses in projects.

THE MORE YOU KNOW.....