What should i do? when i look at a estimate it shows the vat but then when changed to invoice to pdf it does not?

Hey there, @Louis4593.

I'll jump in to provide ways to show VAT within PDF invoices in QuickBooks Online.

QuickBooks gives us the option of how to customise invoices depending on our preference. And decide what information your customers will see, and only include the data that's essential to your process.

Now, here's what we can do to show VAT. We need to Tick the box for the Tax tab.

Here's how:

1. Click the Gear icon and choose Custom form styles.
2. Find your invoice template and click on Edit.
3. Select the Content tab.
4. Click the second box of the invoice template, and put a checkmark on Tax. 
5. Hit Preview PDF. Then hit Done. 

Once done, after you print this transaction at a later time and mark the invoice as Print later, the message will automatically appear. This is to check if you've already printed the invoice from the list of invoices to be printed. Check out this article for your reference: Print multiple sales forms.

Alternatively, after receiving the invoice payment you might want to record them. There are two options on how to record them in QuickBooks. Feel free to read this page for more information: Tracking invoice payments.

Do you want reports showing your total sales? To assist you in using the Reports feature, I'll share the following article: Run Basic reports in QuickBooks.

If you have any additional questions about managing your invoice payments, feel free to write again here. You are more than welcome to include more information in your response if you do have issues with other things, such as expenses or reports. Always happy to assist.