I recognized how crucial it is for you to have the ability to use electronic signatures in QuickBooks Online, blucrew. Having everything streamlined is important, and I'm here to help explore the best options for your needs.
At the moment, QuickBooks Online doesn't have an E-signature feature. This functionality is available via the mobile app, but it's limited to estimates and invoices. Since you're looking for a way for customers to sign documents, such as contracts, a third-party service can be a great solution for those who prefer not to upgrade to QBO Advanced.
For detailed information, you can visit this article for a fast and secure transaction in the mobile app: Capture signatures using the QuickBooks Online app.
I'm including this reference that explains the process of converting an estimate into an invoice: Convert an estimate into an invoice in QuickBooks Online.
I'm just a click away if you need more help with your estimate. Simply click the Reply button below, and I'll be delighted to assist you further. Looking forward to hearing from you!