I have a visa to Canada on my passport, which I have to renew.?
Staple the two passports together, just their covers, so you can see on the inside pages and therefore they will be able to see the visa and your current passport and it will not be easy to lose. Maybe I misunderstood your question. If you have to return the expired passport, then obviously you cannot staple them together. But as far as I know, most governments return the expired passport after they stamp it canceled and invalidate it electronically. If you have to return your expired passport to get a new one and won't get it back, then I suppose you will have to apply for a new visa.