hi, you have to go into view ownership and enable the display of system coordinates. among these you will also find the center of the mass (if it was previously calculated in 3d).
select it and show it like any other part.
if in the draft has been defined a symbol to represent the center of the mass will be displayed, otherwise it will only be a point.
in options as shown in the second image; of course the symbol must be in the draft file used. the advice is to do it on the template. if it is not wrong from different versions the templates provided contain one.