It almost impossible to send the documents online because of the size limit and so your best bet is to send through mail. The letter your wife received from AVO will have the address at the bottom. Please use that or if you are not sure, you can send an email to AVO and ask them for what address to use to send the documents to them.
From the letter my wife got from AVO, they provided the address to send the police reports to at the bottom of the letter. The address provided was:
High Commission of Canada
Immigration Section
P.O. Box 1639, 42 Independence Ave, Accra, Ghana
Fax (233-30) 2 211-524 (visas) -
www.accra.gc.ca
Email:
accra.immigration@international.gc.ca