Question

what is the difference between wavefront and wavelet

Answer 1

All particles equidistance from the sourced vibrating in same phase lies on a surface is known as wavefront..

Every point on a wave front is a source of new disturbance which produces secondary wavelets is known as wavelets.

Answer 2

Locus of all the points vibrating in phase from the source is called a wavefront.
Since wavefront is formed due to vibrating particles these particles will act as the source for the formation of wavelet
Wavelet is also a locus of all the points vibrating in phase except that it's source is the points on the primary wavefront