for which circuit you want value of capacitor?
active filter, 555 timer, delay circuit,
the capacitor value can be found from the design equation like for filter design
freq = 1 / 2*pi*R*C
if you have desired frequency, you just assume value of R (as 1 K, 10 K etc) and calculate value of C. thats all….
type of capacitor depends upon value of capacitor and voltage rating. it can be polarized (electrolytic) or non polarized (ciramic disc)