I have another way on how you use the electronic signatures in QuickBooks Online, Mike2163.

If you want the capability to e-sign your invoices and estimates, you can do this on your phone or tablet when using the mobile app. The mobile app gives you touch-screen capability that is easier for you to perform or accept e-signature. However, if you're sending the email remotely, this option isn't available yet.

If you want to use a third-party app that you can integrate with QuickBooks, you may want to go to the App Center and search for one. You'll have the option to read the app's description and check out the reviews to better give you an idea of selecting the app that works best for you.

You can also refer to this article for more information: Use- E-signatures To Sign Authorization Forms. Also, take time to read these helpful articles so you'll be able to get ideas on the available features that you can enjoy in QuickBooks.

Reply to this thread below and let me know how it goes. As always, you can get back to us anytime if you need further assistance.