Welcome to Orchid Board
As Janet says, the answers depend on the type of orchid you have.
I could guess it's a Phalaenopsis as they are the most common for beginners, but it could be something else.
General advice, is that if the spike dries up and changes colour, then you should cut it off/cut off the dead part.
I think pretty much any orchid will grow a new spike if you cut down the old one. But some it's best to leave, others it's best to cut down.
Photos always help, so we can identify what you have. However most new members find they need 5 posts before they can upload photos. Have a look through some of the photos in Orchid in Bloom and comment on a few and you'll soon have enough.
P.S. I've moved your post to the beginner section. Hopefully that will help you get some answers rather than just folks saying HI in the intros section.