You need to apply for a business (F) visa to China. The requirements: except a properly and truthfully filled out Visa Application Form, one passport-size photo, and a valid passport with blank pages and a photocopy of the data paged, you need to provide the Original invitation from an authorized Chinese organization, travelers cheque, round trip air-ticket, hotel reservation & Ghana company register certificate, tax clearance, true bank statement.
Generally, you do not need your friend's residence or work permit, but possibly you may required to provide additional documents deemed necessary by the visa officer. The round trip from Beijing to Ghana is about RMB 6500 (about USD 977).