Very vague question...
Ecto = small frame, lanky thin, quick metabolism & difficult to pack on weight
Meso = manipulates weight easily, broad shoulders, thin waist, muscular naturally
Endo = naturally fat, big stomach area, slow metabolism, large bone structure (wide)
Eating lots and training hard is the solution to everything. Endos are an exception, they have to eat a bit less than the other two and really monitor the type of calories they're intaking...although this William Sheldon somatype theory is completely outdated and sounds outlandish...but those are your basics.