student Visa or work assistant China viaa

You should prepare a filled-out application form affixed with 1 passport-style photo, your passport and its photocopy, physical examination report, and the work permit from your employer. Next, submit the application to the Chinese embassy to apply for work Z type. For a student X type, you need the JW form and admission letter from your school.

I haven't applied yet in any of the institutions but do you know any of the international institution I can apply online from Ghana here.

You cannot apply online. If you cannot go there in person, you are advised to find an agency or someone to do that on your behalf.