H1B: select the correct category

[gally]

I am about to submit my request for H1B
I have to select the job category. To have more options in case another company wants me, what job category should I apply the H1B visa for?
I am a project manager/community manager/product support

Another questions is: suppose I get the H1B and I get fired by the next company, what happens? Do I have to go back to my country?