I have a pdf that is 1200 pages long which I would like to print, is that possible?
According to the wizards, 800 pp. is the max.
But even if you could, that would be an expensive book for people to buy, and it would be very unwieldy.
If you seriously have 1200 pp. of tightly-written narrative, I'd recommend dividing it into three books of 400 pp. each. There's nothing like a good trilogy. Or better still, four books of 300 pp., which will let you refer to it as the "increasingly badly named trilogy," in the immortal words of Scott Adams (his trilogy included four books and a short story).