Can't send MMS messages (but can receive)
This may help
  
  i have test Moto G
  
  1.Open Message
  
  2.Choose Attach Option on right side Options(Picture,Capture picture,Videos,Capture Video,Audio,Record audio and Slideshow).
  
  3.Choose Capture Video/Videos,if choose video then we have send small video otherwise its not selected.
  
  4.Then last Send MMS.