How to export a music score from Logic Pro X as a PDF
First, select the track and make sure that all sections are highlighted in that track. If only a few of them are highlighted, the quickest way to highlight all of them is to click on a different track and then click back on the track you intend to export.
Join all of the sections so that it is all in one block.
Click on the score tab to see the full score for that track.
Go to file, then print.
Open the arrow next to PDF and select "Save as PDF"