Voucher, award (11)
I believe the answer is:
certificate
I believe this is a double definition.
'voucher' is the first definition.
(thesaurus)
'award' is the second definition.
(certificating is a kind of awarding)
(Other definitions for certificate that I've seen before include "Diploma" , "Exam pass document" , "Film classification" , "formal document" , "Statement of qualifications" .)