Max Shutter speed
Nikon D750 can shoot continuously at max speed of 6.5 fps
and has max shutter speed of 1/4000 sec
D750 has a built-in flash, and it also has a flash shoe to mount your external flashes too.
Nikon D750 features both Contrast Detection and Phase Detection autofocus (AF) systems which ensures speed and accuracy of focusing in most situations. The AF system has 51 focus points and 15 of these sensors are of Cross-type. Cross-type sensors locks focus faster and more accurate compared to single type sensors. Nikon D750 also features Face detection AF
where it intelligently detects the faces in the frame and locks the focus automatically.
You can download Nikon D750's User Manual here