How to specify polarization voltage in polarized capacitors in Orcad Capture
How can I specify that 16V voltage?


You do this: -

1uF 16V


You can even do this: -

1uF 16V 10%


or

1uF 16V 10% TANT


or

1uF 16V 10% ELECT


The value attribute can be however you want it to be.

You can even create new attributes (user defined attributes) than can optionally: -


Be invisible in your schematic
Be seen in your BoM.


On a slightly different note, I would change your symbol to more adequately represent the fact that is for a polarized capacitor. I would also make it less wide so that if you needed to show several parallel capacitors on grid, they don't clash or overlap: -