there are a couple of mel scripts that can be found on the net that will get you started ..one being this one
https://www.creativecrash.com/maya/do...polyshrinkwrap

longer way...
Make a large nurbs sphere around the poly object you want shrink wrapped, turn the sphere into a softbody object and select the poly mesh and make colide finally set a radial field pulling the sphere into the poly object to get the sphere to wrap itself around it.