Here's how:

Go to the Invoices menu at the left pane.
Look for the invoices and click the Send link under the Action column.
Enter the necessary information, and then tap Send when you're ready.

Once done, you can copy the link from your email and send them via text message 

Alternatively, you can visit our QuickBooks App Center to find a third-party application that can directly send invoices to your customers using text messages or SMS.