Camera settings – shooting mode
You'll need to be in one of the Creative Zone modes for this – the easiest one to use is shutter-priority (Tv) mode. This mode enables you to set the shutter speed of your choice, and that's what you need to concentrate on to achieve this effect.
You can of course use Manual (M) mode, if you're confident of the range of settings you need to get the exposure right, but using Tv mode means that the camera will choose the aperture setting for you and the ISO speed too if you switch the camera to Auto ISO.
Depending on your camera, you may have a third option: Panning mode. With the introduction of the EOS M5 in September 2016 came this new automated Scene mode. This Basic Zone shooting mode takes care of theshutter speed settings for you, and you have options for choosing the strength of the effect. The same principles apply – you need to follow the subject smoothly with the camera to achieve the creative effect.