undoing logging on to my iMac

Hi fellow mac-ers,

I was exploring some folders on my home computer(iMac) when trying to set up a VPN connection to my work server, since our IT company said I was on my own since they only know how to set up PCs. I never did manage to make the set up successful but I did end up changing something so now every time I turn on my computer I have to enter my password. Can someone tell me how to turn that setting off?

Riese