French phrase
Quels ~ faut-il joindre ?
Meaning
Which ___ should be attached?
When to use it
A polite question about which items to attach. It is slightly formal and common for applications or emails.
Example dialogue
Quels documents faut-il joindre pour la demande de visa ?
Which documents should be attached for the visa application?
Il faut joindre la copie du passeport et la preuve de réservation.
A copy of the passport and proof of reservation must be attached.