Hybridization of ethanol (CH3CH2OH) molecule can be determined by ethanol's lewis structure. When you know the summation of number of sigma bonds and lone pairs in the last shell of relevant atom, hybridization of that element can be determined.
Both carbon atoms and oxygen atom has sp3 hybridization. But, Hydrogen atom does not show such hybridization because there is only one electron in Hydrogen's last shell.
Each oxygen atom has made four single bonds. Therefore, all those bonds are sigma bonds and no lone pairs exist on both carbon atoms. An example of how to find hybridization of a carbon atom is given below.
Oxygen atom has made two single bonds. Therefore, all those bonds are sigma bonds and two lone pairs exist on oxygen atom.
Hydrogen atom cannot participate to hybridization because hydrogen only has one energy level, no need to find their hybridization. Hydrogen's s orbital has made bonds with sp3 hybrid orbitals of carbon and oxygen atoms.