Can't find default invoice template in quickbooks online, I think I deleted it by mistake

Good afternoon mao7777-gmail-co,

The QuickBooks Community and myself are thrilled to see you here! Before any invoice is deleted in QuickBooks Online, you will receive a prompt message indicating if you truly want to delete the template. Since you are unable to locate it, you can add it back if you have the Docx file  by following the steps below:

1. Go to the Gear icon and select Custom Form Style. 
2. Choose New Style
3.  Select Import and follow the instructions.

 However, if you don't have the file you may need to create a new one. Follow the same steps above but choose Invoice in the third step and make adjustments.

If you have any other questions, don't hesitate to ask me! I will be around. See you soon.