Do it ASAP https://www.canada.ca/en/immigration-refugees-citizenship/services/application/application-forms-guides/imm5476.html
And submit it via web form https://www.canada.ca/en/immigration-refugees-citizenship/corporate/contact-ircc/web-form.html
It might be 2 different requests. For the first one you need to provide documents via web form. For the second you need to update your existing documents.