You can reply to a Conversation by clicking Reply or Add Message. Selecting Reply copies the previous message, like in an email, but limits your reply to the same channel the conversation is in. The Add Message option allows you to add a response in different channels.
Important Note
You cannot reply or add messages to a closed conversation.
Instructions
Navigate to the Conversations tab

Click Go to Conversation Details for the desired conversation

Click Reply or Add Message

Reply: Copy the previous message and respond in the same channel

Add Message: Respond to the conversation using any channel

Type your response

Click the Add Attachment link to add any desired attachments

Note:
The file size limit for an attachment is 20 MB.
Click Send or Log:
Send: Send your Reply

Log: Send your Message
