Shares are tokens of ownsership and the proportions of how they are distributed depends on how many shares are issued in the beginning.
If, for example, 100 shares are issued and you have two shareholders with 50 shares each, they would both be 50% shareholders.
If you issued 10 shares, one shareholder having 4 shares and the other 6, the second will have a 60% share and will be the main shareholder.
Each share has a monetary value but this does not have a true bearing of the value of the share and the share worth is normally worked out after the value of the business.
Shares can all carry the right to dividend and the shareholders may also benefit from the sale of the company.