Small business =>   borrow from bank, hire purchase or leasing
Larger business => Advantage, selling more shares.   Instead of borrowing (paid back later), they obtain permanent capital (have to paid dividend on which new shareholders expected).
Public company or public limited company can invite the general public to subscribe for shares.   But private company is prohibited from offering its shares to the general public.  
Large public limited companies, have the right to sell their shares to the public and wish to be quoted on the London Stock Exchange.   Issue share capital is usually in the form of ordinary share (equity).   The ordinary shareholders are the owners of the company.   The Stock Exchange is in effect a second hand shop, bring buyers and sellers together, so that persons becoming shareholders of any plc quoted on the Stock Exchange can always get an up to date valuation of their shares and sell them through Stock Exchange member firms.  
Except this, company can retained profits and other reserves kept iwthin the company rather than paid out to shareholders as dividend.  
Company can borrowing from bank, or investors can purchase debt securities issues by the company.   The company promises to repay the debt at certain date in the future, and pays the investors interest on the debt.   Debt capital includes debentures, Eurobonds (bought and sold on an international basis) and commercial paper.  

Affect both balance sheet accounts and income statement accounts.
Simultaneously, the changes of financial statements will affect performance ratio.
Better control of working capital, use retain earning and not distribute the dividend to shareholders:
Company use retained profits affect cash and equity=> Retained Earnings decrease in balance sheet.
Control stock:   Inventory decrease, Sales Decrease in Income Statement, but Account receivable will decrease from customers and account payable will decrease...