A residence permit is conditional — tied to your purpose (work, study, private affairs) and renewed as circumstances change, usually yearly.
PR is purpose-independent: once approved, you can stay, change jobs and travel freely. The bar is much higher and review is stricter.
Short-term work or study? A residence permit suffices. Planning to settle, educate children or buy property? Start planning for PR early, since several pathways require years of qualifying residence.