hey I'm looking for a css server host and I have some questions because do i get adons with the server or do i need to find them myself + do yo give support on addons

and do i need a Voice Server (ventrilo teamspeak mumble) to be able to talk on the server ?

Servers come with a few add ons to get you started and if you need help putting in a new mod support will install it for you if you pop in a support ticket. You dont need a team speak or ventrilo server to be able to talk on the server, however they are useful for talking to your mates whilst playing the game to save using the voice on the server that everyone can hear

Once you have created a CSS server, will it work on Half-Life?

No