No, you’re not missing anything. Extensions are not supported in interfaces.
If you don't mind sending your users back to the grid view, you can do that with a button. Then, they can use the Page Designer extension over there.
Otherwise, if you want to be able to create documents from interfaces, then you would need to turn to 3rd-party document creation apps to get that functionality.
Here are a few options:
1. One of the most popular PDF creation tools for Airtable is DocuMint. This can be automated natively or by using Make’s DocuMint automations.
2. Another popular tool is Docs Automator, which integrates with Google Docs.
3. However, you can choose ANY document creation app that you would like, and automate the PDF creation process by using Make’s automations & integrations. You can even use good old fashioned Google Docs, Microsoft Word, or Microsoft Excel.
If you’ve never used Make before, I’ve assembled a bunch of Make training resources in this thread.
For example, here is how you would instantly trigger a Make automation from Airtable.
p.s. If you have a budget for your project and you’d like to hire an expert Airtable consultant to help you with any of this, please feel free to contact me through my website: Airtable consulting — ScottWorld