Vout(s)/Vin(s)=1+RCs assuming no initial conditions. The transfer function is a simple "real zero" which is represented in Bode plot like I drawed. When ω=1/RC the amplitude is sqrt(2) and in dB is 3 dB.
When ω<<1/RC amplitude is ≈1 meaning 0 dB.
When ω>>1/RC amplitude rises with +20 dB/dec.
If ask me more specific question, I know where to focus...