Where to find the Adsense amp-ad code?

Answer

AMP pages require ads to be in the <amp-ad>-format

If you are using Google Adsense you can find the code as follows:

1. Go to AdSense
2. Open Ads > Overview in the left side menu
3. In the top click By ad unit
4. Form the resulting page, find the ad you want the code for and click the < > icon
5. In the box that opens up, click on AMP
6. Copy the code from "Step 2 " (Step 1 is automatically added by AMPXF)