Basic Digital Filter [Arduino Uno]

can someone pls help me making a digital filter using arduino uno. thanks

For audio you should sample at 44kSPS or above unless you have a brick-wall hardware anti-aliasing filter,
otherwise you'll be plagued by aliasing noise - once sampled aliasing cannot be removed.

In other words the Uno's default 10kSPS limit is inadequate, an external SPI ADC would be a better
idea, using a timer-driven ISR to sample at a precise regular rate (failure to sample at a precise
rate will also inject lots of noise into the samples than cannot be removed).