The Hong Kong guide lists the forms the applicant needs. Then it says to send these forms and the other documents to the sponsor. The sponsor has to put all this together with the sponsor forms. IMM1344 is not listed in the Hong Kong guide because it is a form for you, the sponsor. The link I posted above should go to this page. You have to send in:
Part 1: Sponsorship forms
Guide to Sponsorship [IMM 3900]
Document Checklist [IMM 5491] (PDF, 878.79 KB) February 2016
Application to Sponsor, Sponsorship Agreement and Undertaking [IMM 1344] (PDF, 539.27 KB) August 2014
Sponsorship Evaluation [IMM 5481] (PDF, 584.73 KB) April 2012
Statutory Declaration of Common-Law Union [IMM 5409] (PDF, 636.51 KB) April 2015
Sponsor Questionnaire [IMM 5540] (PDF, 1.07 MB) April 2008
Use of a Representative [IMM 5476] (PDF, 648.31 KB) September 2015
Part 2: Immigration forms
Sponsorship of a spouse, common-law partner, conjugal partner or dependent child living outside Canada [IMM 3999]
Forms
Generic Application Form for Canada [IMM 0008] (PDF, 496.57 KB) November 2015
Additional Dependants/Declaration [IMM 0008DEP] (PDF, 424.19 KB) August 2014
Schedule A – Background/Declaration [IMM 5669]) (PDF, 776.39 KB) December 2012
Additional Family Information [IMM 5406] (PDF, 570.00 KB) September 2013
Sponsored Spouse/Partner Questionnaire [IMM 5490] (PDF, 139.87 KB) August 2013
Use of a Representative [IMM 5476] (PDF, 648.31 KB) June 2015
Plus anything else not mentioned that is mentioned in Part 3, the guide for Hong Kong.