Private company ownership

Question: How would a private company such as a limited partnership issue shares among its partners. How would such a process work?

Extra info: Of course when a business is in its early stages, ownership and profit splitting is left to the typical "you get what you put in". But there comes a time when a decent amount of money is being made and the old rule becomes a bit harder to work with as each member has differing circumstances.

To avoid things getting messy, how would a private company normally do it? What are the decision making rules behind number of share authorised, share par value etc.