Hrdrogenation is a process to obtain saturated hydrocarbons from unsaturated hydrocarbons.
See a common example :-
The unsaturated hydrocarbon ethene is reduced to ethane.
The conditions require pressure (different for different reactions) and catalyst such as Ni, Pd, Pt...
The Physical properties might change as follows :-
(i) Unsaturated hydrocarbons are mainly insoluble in water but saturated are soluble. Therefore the insoluble becomes soluble .
(ii) The boiling point and freezing point changes as accordance to the compounds.