Eighth generation desktop processors need extra accessories in order to activate Video Graphics Array output.
Intel website shows that the graphics output of 8th generation processor are HDMI/eDP/DP (High-Definition Multimedia Interface/Embedded DisplayPort/DisplayPort). However many motherboards in the market can also output VGA. If I have an 8th gen processor and a motherboard with VGA port, can I multi-stream both HDMI and VGA port?
Different processor lines have different support features. In this case, U and Y series are not supported as they are mobile processors and the laptop designer won't use that function. For desktop processors, it may support but needs DP-to-VGA converter and an external dongle.
More information related to display interface of 8th gen processor is available at datasheet page 40.