For successful export to the Tango P-cad format (Altium supported), you need to know a few nuances.
Move the origin to the lower left edge of the board to exclude the negative coordinates of any objects from the design.
RefDes should not contain special characters, such as .- \ /% # *, etc.
Multipins will be divided into different pins since not supported in this format
Inverse polygons are not supported and will be converted to regular polygons.
From the right-click menu of the Infobox window, select the Export P-cad menu item