How do I change a discrete 3-D surface into a continuous 3-D surface whose exact surface equation is not known?

If I have some data points recorded on a 2-D matrix and plot it to obtain a 3-D surface, how should I change that surface into a a continuous surface and obtain an equation of the surface?

Answer 1

[KSSV]

doc fit

https://in.mathworks.com/help/curvefit/fit.html