Load an audio file, read its current sample rate and pick the target rate you need. Press Resample and download the converted WAV at the new rate.
44.1 kHz is the standard for music and 48 kHz for video work. 16 kHz or 22.05 kHz are common for speech and voice assistants because they cut file size sharply while keeping speech perfectly intelligible.
It removes frequencies above half the new sample rate, so going to 16 kHz discards everything above 8 kHz. For speech that is usually inaudible; for music with cymbals and air it is clearly noticeable, so downsample deliberately.
No. Upsampling interpolates new samples but adds no detail that was not already there. It is only useful for matching the rate of a project or device that requires a specific value.