Will iMessage receiver on iPad see my iPhone number?
From this Apple Support article:


  
  For Messages, go to Settings > Messages and make sure that iMessage is on. If asked, sign in with the Apple ID you're using with Messages
  and FaceTime on your iPhone. Then tap Send &amp; Receive.
  For FaceTime, go to Settings > FaceTime. If asked, sign in with the Apple ID that you're using with Messages and FaceTime on your iPhone.
  Turn your phone number on or off:
  
  
  To turn on your phone number, select it and your Apple ID in the “You can be reached” section. If you don't see your phone number, get
  help with your settings or contact Apple Support. If you see a number
  that isn't yours, change your Apple ID password.
  To turn off your phone number, uncheck it.
  
  


Once you turn off your phone number at the "You can be reached" section people will see your email.