To send message, go to Communicate > Notice Board. here you can notice board page along with old message if available will showing in right.
Now, click on Post New Message button showing at top right corner in the notice board page, at click of this button it will redirect you in the Compose New Message page.
here enter the details message Title, Message, Notice Date and Publish on, attachment file, Message To (Select those you want to message) and then click on Save button.
Here you can view posted message in the notice board page.
If you want to see the file that you uploaded as an attachment, go to the notice board and click on the message that you sent; the model page will open from the right side; here you can see the download attachment with the download icon; by clicking on this, you can download the file that you uploaded in the post-new message.
To edit posted message click on Edit icon and to delete posted message Delete icon present in notice board page.