If you want to become a successful singer you need equipment to do so. You cannot just randomly become a professional singer with only a good voice. Without the equipment you would not be able to record properly and express your greatness in singing. It may cost a lot of money to get the equipment needed but there are cheaper and easier ways out of it.
To start off with recording you need some type of voice recording equipment. You need this to see if you are actually improving. Without the recording equipment you cannot hear how you actually sound. If you do not listen to yourself singing by recording it than you cannot hear if you are getting better. If your voice cracks and the pitch is not working you want to be able to hear that yourself. The recording equipment is very useful for that.
If you are starting to write your own songs you need somewhere to jot your ideas down. Song lyrics can come up in your head at any time and you need a place to write these lyrics in. You could use either a notebook or your phone to jot down your ideas. A phone would be more useful because now-a-days it is attached to your hip.
Another piece of equipment you obviously need is a microphone to sing in. If you are too quiet you will not be able to hear your true voice. To make your music sound better you would also need a mixing console. This would help you combine your music or change the level of it.
To publish your music and get it out where you want it you would need some sort of technology. Some laptops have applications that you can edit your music on, such as GarageBand.
To sing for enjoyment you do not need all of this equipment. If you sing a certain genre of music you may need other equipment to make your music better. If you have to basic equipment it will help you seek out bands and/or gigs. This would help you get your name out there and people would want to hear more. If you want to make a career out of singing then you need the equipment to become an overall better singer. Without the equipment your singing would not improve and a producer would not seek out to you.