In the United States, the President is the most powerful and prominent public official. He or she is elected every 4 years and runs the day to day operations of the government. Any eligible citizen can run for the office, though winning the position requires a lot of time, money, and dedication you can use other people's time, money and dedication.
It costs $450 million dollars to run for President if you are an arrogant, fake-socializing, schmoozer that pays retail for everything and contracts every service because you don't know how things actually work. For example, millions of people pay $120.00+ per month for Comcast cable TV while knowledgeable people pay $10.00 per month for their TV and get more than Comcast provides. You can run for President, and win, if you are smart, technically savvy and do everything yourself with a small, tight, clever team that knows how to work mass media networks.
You have to have smart ideas, that can really work and you need to be able to think on your feet. Most past Presidents were dyslexic/autistic. That is why they could instantly go on-and-on about any subject. Robin Williams had this kind of 'instant output' mind. Gavin Newsom, Donald Trump, JFK and many other famous politicians had ramble brains. The media loved that they could fill airtime with hot air that sounded good.
To get other people's money, you will have to promise them things that Congress, The U.S. Treasury and common-sense will never actually allow you to do. You lie, shake hands with some tech billionaires and rich widows and you will have at least $30 million in no time.
Before you decide to run, you need to meet with, at least, 300+ citizens that you do not know, in little town halls, and have them ask you questions about your platform and see if they can shoot you down. 95% of potential candidates can't make it through this phase, without having a nervous break-down, so challenge yourself with this effort before you do anything else. Save yourself the time, money and sanity on this phase above, and before, all else.
Billionaires are often assholes with too much money and heads so big that they think "They should be President". They often run for President and lose because they are tone-deaf to the real world.
Generally, candidates spend 2/3rds of their time and money fighting defamation and character assassination attacks from their opponents and special interest groups and the other third of their money attacking those two group. A weak mind will crumble under such an onslaught.