Select the type of media you wish to send.
After selecting Send Picture, Send Video or Send Audio you will have the option to either record the media or choose an existing file. You can add a caption to any photos or videos before sending them.
To send a Voice Message, press and hold the space bar of the keyboard. Learn more about voice messages in this FAQ article.
If there is no Send option, it is likely that your music is forward locked. Look at the properties of the music to double check. Unfortunately, WhatsApp can not send audio that is forward locked.
If you wish to forward media or a message, you can highlight the media or message and press the f key on your keyboard to send it to one of your contacts or groups.
If there is media that you wish to send from your phone that is not appearing when you try to choose it from the app, first make sure you have the media saved in your Media Folder, then open WhatsApp, and it should be available in the dialogue presented.