Welcome to the QuickBooks Community, dishedbyrachel. This isn't the kind of feeling that I'd wish you to have and I can see how the Tips feature is essential for your invoices. With this, I'll ensure to share further details on how Tips works in QuickBooks.  

As mentioned above the option to use the tip feature when creating an invoice is currently unavailable. You can only use the said option in the sales receipt. Then, creating an item to add as a tip to your invoice is the workaround you can perform.

Furthermore, you can only use tips with the New Airy template. If you want to use another template, try recording a tip or gratuity in QuickBooks Online.

Additionally, you can also send feedback to submit a request about using the Tips feature in the invoice. Any recommendations are sent to our engineer for consideration in future updates. To do this, I recommend going to the Gear icon in QBO and choose Feedback.

Lastly, you may refer to this article to see details on how the Sales page provides you a great at-a-glance view of the status of all your sales transactions: View sales transactions.

Let me know if there's anything else you need help with managing your customer's entries or other QuickBooks-related concerns. I'm always here to help you anytime. Take care and keep safe!