Hi there, 

Creating custom sales forms is a great way to reflect your brand image in QuickBooks Online. I know how important it is to be able to import your custom styles easily, and how handy it is to preview your PDF. I'll help you with both of those questions so you can get back on track. 

First, follow the steps here to import your custom form styles: Import custom form styles for invoices or estimates. As explained in this article, you'll follow 4 simple steps to do this.

Step 1: Map your template fields

Step 2: Save and upload your DOCX template

Step 3: Match your fields with QuickBooks fields

Step 4: Preview and confirm your style

Now that you've been able to upload your custom styles, it's important that you have the option to preview your invoices or estimates before sending them to your customers. If you're not able to review the template by clicking Print or Preview, there may be a browser-related issue causing loading or latency issues. 

Try clearing the cache and cookies in your web browser to remove any stored Internet files. These stored files can cause bugs in QBO and other sites. Here's how to clear them: Clear cache and cookies to fix issues when using QuickBooks Online. 

If the issue persists, try using an Incognito window in Google Chrome. This is a private browsing mode that operates separately from the main browser, and it doesn't get impacted by stored cache and cookies. Here's more information about that and how to use it: Browse in Private. You should also try using multiple different browsers.

I hope this helps get you back on track. If you have any other questions, please reach out to our tech support team.

Cheers.