Can i place nothing?

[+the_killer_crew]

for a virtual cache, can i leave nothing and just make one?

[geoawareUSA9]

That is how virtual caches work, yes. But you can only place a virtual cache if you have been given a Virtual Reward to place.

 

You can place an Adventure Lab, lab credits are much easier to come by. Or a Waymark.

 

Or, if there is a unique earth science feature, you can try your hand at submitting an EarthCache.

[+the_killer_crew]

How do i make a virtual reward?

[Keystone]

I merged together two threads about the same subject.  The answer from geoawareUSA9 to your first question also answered your second question.  To repeat, you can read more about Virtual Caches, including links to explanations for Virtual Rewards, in this Help Center article.