Is the NMR technique based on the element carbon only?

NO.

We can perform

1H (Proton) NMR

31P (Phosphorous) NMR

19F (Fluoride) NMR

C-13 NMR

no,

1H

19F

31P

Or element with odd mass number

NMR based on carbon and hydrogen and other elements NOT on carbon only 

No , other isotops can be used such as:

1H, 13C, 19F and 31P

No, it is used for all the element whose nucei possess magnetic moment (nucei with odd number of protons or neutrons) are NMR active. Most commonly studied elements with NMR are hydrogen (1H), Carbon (13C), Fluorine (19F), Phosphorus ( 31P). 

NMR can be used with any nuclei whose spin number is greater than zero.

NMR TECHNIQUE BASED ON THE ELEMENT 1H (Proton) NMR

No, NRM is a research technique that exploit the magnetic properties of certain atomic nuclei. This type of spectroscopy determines the physical and chemical properties of atoms or the molecules in which they are contained

1H, 3C,  19F, Silicon, copper etc. It is effectivley used as qualitative and quantitative techniques.

No, other compounds such as H, F and P can have NMR Spectroscopy.

No,This technique is usefull for Fluorine, Carbon, hydrogen and phosphorus