I appreciate you for joining this thread, @Oliver Wassef.

We've heard your concerns, and I'd like to inform you that the option to add tips to invoices is now available in QuickBooks Online (QBO). 

With an active QuickBooks Payments subscription, your customers have the chance to tip 5%, 10%, 15%, or a custom dollar amount when paying an invoice. Also, please note that this is only available in the new invoice and estimate experience. 

Here's how to turn tips on:

1. Go to the Gear icon and select Account and settings.
2. Click Sales, and in the Sales form content, select Edit.
3. Turn Tips (Gratuity) on.
4. In the Who's receiving these tips? window, choose an option between My Team and Just me.
5. Click Update.
6. Select Save, and Done.

Additionally, please follow these steps to manage tip settings from an invoice:

1. Go to + New and select Invoice.
2. Click ⚙ Manage, then select Payment methods.
3. You can switch Accept tips on or off for this invoice only.
4. You may also turn tips on or off for future invoices. Under Accept tips, click Manage settings. Choose Who gets tipped and turn tips on or off.
5. Click Save.

If you want to make your sales forms look professional and personalized, you may also customize them.

Please let us know if you have further questions about adding tips to invoices. We're always available to provide our assistance. May you have a fantastic week!