The ASRock Z170 Pro4s only has an HDMI and a DVI-D integrated graphics video output.
You'd only be concerned with such motherboard's video output ports IF you are going to use the integrated graphics of the CPU. Since you will be buying a dedicated GPU (i.e., the Asus GTX 1060), you can use the video outputs of the dedicated GPU to connect your monitor to.
Note that the GTX 1060 (as well as other GTX 1000 series), do not have any VGA (analog) ports anymore (they only have DisplayPort, HDMI, and DVI-D, which are all digital). So, if your monitor only has a VGA input (analog input) and nothing more, you need to buy an active HDMI-to-VGA or active DisplayPort-to-VGA, or active DVI-D-to-VGA adapter for this purpose. But if your monitor has a DVI-D or an HDMI or a DisplayPort, it is advisable to use such ports.