The official publisher, (Hathras, India), holds the copyright to the most accurate modern printing. They do not offer a free PDF, but they do offer:
: A six-part practical textbook series. It is essential for students as it contains notations for approximately 1,200 classical compositions across all major Ragas. Alternative Formats Bhatkhande, Sangeet Sastra Vol.1 - Internet Archive bhatkhande sangeet shastra pdf free upd
If you manage to download the PDF, here is how you should navigate it: The official publisher