After i upgraded my software on my iphone, my itunes disappeared and i've never downloaded any music and I want to put music on my phone using itunes. How do i get it back on my iphone?

Did you lose iTunes from your phone or from your computer? You posted in the iTunes for Windows forum, but you said "How do I get it back on my iPhone?"

Assuming you are referring to your phone... the iTunes app cannot be deleted. Maybe it got restricted. Check under Settings > General > Restrictions.