unable to distinguish between thickneess of object line and extension line on drawing in creo parame

Hi,

line thicknesses are not normally set in the Creo window. To set line thicknesses in PDF or paper print use pen table.

If you want to see the line thickness/color differently for dimension lines compared to drawing view geometry line in the PDF output then you can use the pen table file. Refer to the article https://www.ptc.com/en/support/article/CS25880