CIDFont F1, F2, F3, F4, F5, F6, and F7 are not actual font names you can download; rather, they are internal generic labels
Now, for the most critical part of this article: how to download these fonts . cid font f1 f2 f3 f4 f5 f6 f7 fonts free download link
Since you cannot download "F1," you must identify the it is substituting. Check Document Properties : Open the PDF in Adobe Acrobat . Go to File > Properties > Fonts . CIDFont F1, F2, F3, F4, F5, F6, and