I replied to your PM few minutes ago...
Yup, save as pdf file and follow below instruction of CEM indicated at the letter sent to you...
Fees may also be paid online at https://eservices.cic.gc.ca/epay/welcome.do?lang=en
Upon successful completion of your online payment, a PDF receipt will be sent to the email address provided during the online payment registration process. Please retain a copy of the receipt and forward the receipt to MANILIMMIGRATION @ international.gc.ca with the following information:
Subject line: Payment for E12345678
Body: Full name and date of birth of the principal applicant
Then don't forget to rename the file as per instruction...
File name of each PDF document must follow this format:
Application number<space>Last Name<space>Given Name<space>Type of Document