Does a PR travel document application require proof of why I was outside Canada?

Generally, yes. A PR travel document application typically requires the applicant to explain, and support with documentation, why they were outside Canada, since the officer needs this information to properly assess the residency obligation calculation and whether any recognized exception, such as accompanying a Canadian citizen spouse or qualifying employment abroad, applies to the time in question.

Without this explanation and supporting evidence, the officer has no way to distinguish between time abroad that should count differently under an exception and ordinary time away that simply counts against the residency day total. This is also directly relevant where the applicant is relying on humanitarian and compassionate factors to overcome a shortfall, since those factors depend heavily on the specific reasons for, and circumstances of, the absence.

Anyone applying for a PR travel document should gather clear, organized evidence supporting the reasons for their time abroad before applying, rather than assuming a general statement will be enough, since the strength of this documentation can materially affect how the application is assessed.