Here is the information about what is passports and what is travel documents this is about Canada but should be same kind of idea everywhere... try to search your country’s passport website it should b explained on there too...
https://www.canada.ca/en/immigration-refugees-citizenship/services/canadian-passports/travel-documents-non-canadians/document-types.html
When they say passport or travel documents basically they r asking passports (for general public) i had same thing written in my email in-fact every passport request email or document will have the phrase... when u send passports they will put visa sticker for IM-1 Immigrant category and give u a Copr (confirmation of permanent residence). Once u get these things u need to go out the country (Canada) if ur already in canada to become a permanent resident then they will cancel ur immigrant visa u will b pr in Canada.
If ur outland applicant then ur already outside Canada u just need to buy tickets and come to canada...(with immigrant visa and copr of course)
i think these immigrant visa have only 6 months validity so u have to enter into Canada before it expires
Hope it helps