When generating an invoice it is not giving me a preview and when I try and send an email it is not producing the invoice on the email.

Creating an invoice normally allows you to view the form preview. However, QuickBooks Online (QBO) depends on the PDF viewer installed on your browser, @physioforpaws. As for sending an invoice via email, we can set up your account's Online Delivery and choose your preferred email option. I'll guide you through the steps.

First, we need to navigate through the Account and Settings, here's how:

1. Go to the Gear icon.
2. Select Account and Settings.
3. Go to Sales.
4. Click Online delivery, then check the box that says, PDF Attached, then choose an option to if you want to show full details or a summary.
5. Hit Save.
6. Then, click Done to save successfully.
   
   
   
   

Then, let's try creating a sample invoice and send it to your personal email and check to see if it works.
 

After doing so, if there's still no PDF attached to the emailed invoice, let's try logging into your QBO account using a private or different browser to eliminate any potential webpage or browser issues that may cause it to behave unexpectedly. Then, create an invoice and check if you can view the form preview. Also, try sending it again to your email.

Additionally, you can refer to this article if you want to handle multiple forms at once: Email or print multiple sales forms in QuickBooks Online.

Moreover, you can also refer to this article to assist you in designing and personalizing the sales forms you send to your customers: Customise invoices, estimates, and sales receipts in QuickBooks.

If you need further assistance with managing your sales forms, just leave a comment below. I'm always here to help.

If you’re referring to the IOS app, the print/preview issue started with an update about a week ago, and is currently still ongoing.

Quickbooks are working on fixing on case INV-121598.

It affects all previews, eg invoice preview, payment preview, attachment preview etc.