You dont have partners in a normal ltd company, you have Shareholders who each own a proportion of the company
Shareholders own the company and can also select the Directors who run the business for the shareholders
Shares can vary from a simple allocation of the same type of share to different combinations each which may have voting rights of some sort, or may not have them, and some entitled to dividends if the Directors vote on issuing them
Share certificates are issued by directors who also send in the completed forms to companies house and also notify CH of any changes
Shareholders agreements are complicated and in reality need to be written by a lawyer as they can solve many problems at a latter date by pre thinking them out and making a contract between the shareholders on what will happen. for instance someone leaving the company may have to offer the shares to a existing shareholder based upon a agreed settlement rate before offering them to a outsider. Each is different and well worth the cost
A Director has legal obligations and duties to the company and all directors can be held responsible for the company's actions, Its important to read up on these responsibilities and also the power of shareholders based upon their percentage of shares they own. Its not just a title