I'm sure way down the list, there is a socialist candidate trying to run for president. I have no idea about who that may be.
In general, around the world...socialism is defined as a system where the major industries that provide basic needs are owned by the govt and accessible to all equally. Other things are owned by private businesses.
Some things you see in a socialist country: universal education, universal health care, govt owned utilities and logistics companies (such as railroads and airlines) and govt owned media, and fuel processors. I think this may even include major food growers but I'm not sure. I think the food retailers are private companies most of the time. I think in some socialist countries, the religious organizations are also in cahoots with the govt or at least are govt funded. For example, everyone born in England is automatically recorded to be Anglican...everyone in Germany is recorded to be Catholic...the choice however, is yours to practice, choose another faith, or not practice religion at all.
Every citizen in a socialist country has equal access to the services that the govt provides, and if you are in that business (such as a doctor), the govt is your employer. This is why taxes are so high. It's like your taxes include an all inclusive insurance policy, among other things, that includes everyone instead of just those who wants the coverage or chose that provider.
Things may vary country to country.
The argument against socialism is that when govt steps in to run these things, the industry has nothing to compete against to keep it in check, resulting in lesser quality, inefficiency, higher prices, and no incentive to complete research to advance that field.
The argument for socialism is that with the govt ensuring certain things like medical care and education...you have a good start on being a productive citizen without making financial excuses for it, then you can do whatever you want with your life to make your own money. In addition, socialist theory is that if everyone needs a certain thing, like phone service, roads, or access to travel, or the right to a newspaper...the govt can sponsor it and streamline the process. In the case of socialized health care...it would be a govt sponsored insurance company where everyone pays in, at lower premiums, to pay for the needs of whomever is sick at that moment. In a private system, the larger the pool, the lower the premiums. So if everyone is paying into the same pool, theoretically the premiums will be as low as they can get.