What are the differences between HPLC and GC for sample preparation and to investigate the result? and the differences between them and GCMS for example ?

Gc means Gass chromatography ,it can only able to detect those compounds which have ability to evaporate within a temperature range upto300 degree's or more under special conditions.sample for GC should preferably be prepared through steam distillation process .on the other hand HPLC is parallel to LC(liquid chromatography ) it can detect most of the compounds with out converting the sample into gaseous form , standards are required in both cases.GC-Ms means mass spectrometer is attached with GC , in this case when the sample evaporates and get ionized , MS reads there striking speed and distences and give us a spectrum  , due to these fregmentation patterens we are able to read the structure of expected compound.