Normal copies are fine if the checklist doesn't specify a certified copy. Usually the only thing that needs to be certified are document translations. If the birth certificate isn't in English or French and/or there's no option to get an international birth certificate that has international languages included, then you must make certified translations of it, and same goes for any other official documents they ask for.
Otherwise normal copies that one can make at home are okay. All of our documents were homebrew copies except for my police certificates that I had to translate and certify said translations (my country issues international birth certificates upon request so I was good when it came to that).