Some scores do not feature a download button because the uploader has decided to disable the score download option.
This is usually related to copyright concerns. Whilst you cannot download the score, you can still "Save to PDF" and print it. Here’s how:
First, click on the “Print” button
Select “Save as PDF”
If you’re an uploader who wants to block downloads of your score, please tick the “Disable the score download” box during your upload. This can be found in the ‘Copyright and download’ settings.