I know how important it is to be able to text message clients' invoices. However, the feature is currently only supported in the old invoice layout. I have some alternative solutions that you can use, marcycpa.
 

If your customer has QuickBooks Payments and has chosen to receive text notifications, you can easily send them invoices through a text message. To do so, follow the steps outlined below:

1. Select Sales, and then Invoices.
2. Find the invoice you want to send and select Send from the dropdown menu ▼. If you want to review the invoice first, select Edit instead, then after you’re done, Review and send.
3. Click Text and follow the steps.
    

For customers not using QuickBooks Payment, you still have the option to send invoices via text by sharing the invoice link. Here's how:

1. Open or create an invoice and click the drop-down arrow next to the Review and send button.
2. Click the Share link, and make sure to double-check the transaction date.
    
3. Choose the Copy link button and click Done.
    
4. Once done, send it and share the invoice link via text message outside QBO.

We currently cannot provide a recommendation if you're looking for a specific application. Nevertheless, QuickBooks Online (QBO) works with various applications that you may find useful. Just navigate to the Apps menu and select Find apps.

For additional guidance on simplifying the payment process for your customers, you can check out this article: Send An Invoice To A Customer in QuickBooks Online.

Additionally, learn how you can record invoices in different ways, I've added this article for more details: Record Invoice Payments in QuickBooks Online.

Did you know that our QuickBooks Live Expert Assisted team is readily available to assist you with your customer transactions and reports? They can help ensure you have a clear understanding of your business's financial status at all times.

Let me know if you have further questions when sending invoices. I'm always right here to help.