Customise and print/review buttons won't work on tablet. How to fix it?

Let's get this working for you, scubaphil29.

If you're using an Android tablet, the option to customise sales forms is unavailable. We can get more details about this in this article: Customise invoices on the QuickBooks Online mobile app. 

If you're using an IOS tablet, performing the recommended basic troubleshooting steps will resolve the issue.

To get this sorted out, as an initial step, let's clear the application's cache files. Doing so helps in fixing any sort of unexpected behavior in the system.

For iOS:

1. Go to Settings and click Setting General iPhone Storage.
2. Choose an app that's taking up a lot of space.
3. To free up the storage without deleting the documents and data for the app, hit the Offload App.

Once refreshed, restart your tablet and check if we can customise, and print/review from there.  If you get the same result, uninstall and reinstall the QuickBooks Online app.

However, if the issue persists, I'd suggest accessing your QuickBooks Online account via the web browser on your tablet and customise the forms, and printing/reviewing from there.

I'll be sharing with you this article: QuickBooks Online app overview. We can find details on what information we can find in the mobile application as well as the recommended operating system.

You can always get back to me if you have any follow-up concerns about customising sales forms in the QuickBooks Online app, scubaphil29. I'll be delighted to help you as long as I can. Have a great rest of your day!