Disclaimer: I’m not a Democrat.
But generally speaking…
A belief that the healthiest economy is one that feeds and comes from the middle class rather than the top percentiles. Therefore, they believe in greater taxation of the rich and large corporations and closing tax loopholes used by them, and greater breaks to the middle class and poor. Some on the right will call this approach socialism, although that is really a gross misrepresentation painted by the right to scare people away. Biden, Sanders, Warren, AOC, etc all believe in capitalism and have zero intention of doing away with it - what is needed for true socialism to occur.
A belief in greater regulation on large corporations and reducing their influence on politics.
A belief in a strengthening of the safety net for the middle and poor class, including, but not limited to, accessible and robust healthcare, family assistance, free and/or affordable education, and well-funded social security.
A belief in strengthening of unions for the working class as a means of ensuring better worker conditions and pay.
They usually are big on saving the environment.
Less spending on defense.
More welcoming to immigration and asylum seekers and forgiveness of illegals.
More spending on public education.
Greater gun restrictions.
Easier access to voting.
Pro-choice. LGBT rights.
Some I am in agreement with, some I am not.
What the real socialists
intend to make happen is a new party or newer faction to take over the country. This take over could be through violence but more likely through political maneuvering. Then they will consolidate control by eliminating those they deem dangerous to their continued rule. The other parties will be banned. Religion will be criminalized and replaced by their quasi psychology. They will nationalize all major industries particularly news and communication.