How do I reply to or forward a message?
Replying keeps the conversation thread: the other person sees your reply below their message.
Step by step
Open the message you want to reply to.
Above the message, click Répondre (Reply). To also reply to the other people on the message, click Répondre à tous (Reply all) instead: it includes the people in Cc, never those in Cci (Bcc).
The window opens already filled in: the address, the subject starting with « Re : », and the original message underneath, with its formatting, after a gray line.
Write your reply at the very top, then click Envoyer (Send).
To pass the message on to someone else, click Transférer (Forward), type their address in À (To), then click Envoyer (Send).