The reply box has multiple functions to design your message.
Fields / Functions
Change the text format to
Change the text format to bold (and backward)
Change the text format to italic (and backward)
Change the text format to underline (and backward)
Change the color of the font
Upload an attachment
Upload an image to the text
Mark a text and click on Add Link
You can use text templates to enter it to your message.
The message automatically saves as a draft. You can delete the draft at any time.
Click on the button to send the message. If you click on the arrow, you can
A signature can add automatically. Check the Settings > Channels to configure the signature.