Conformational isomerism arises due to free rotation around 
C-C single bond. Hence conformational isomers have same 
molecular formulae and same physical/ chemical properties 
but just spatial arrangement of groups differ. For eg. 
staggered and eclipse form of ethane and boat and chair 
form of cyclohexane. As the energy required for 
interconversion is very small, conformers can't be 
seperated.
Configuration isomerism arises due to some rigidity in the 
molecule. For eg. geometrical isomerism is due to 
restricted rotation around C=C bond while optical isomerism 
is due to assymetricity in the molecule. Both these fall 
under configurational isomerism. Configuration isomerism 
have same molecular and structural formulae but differ in 
one or more properties. We can seperate different 
configurational isomers.Eg. malaic acid and fumaric acid.