You can respond to texts sent to your Masked Phone number but you can't initiate a text conversation without revealing your real phone number.
To reply to a text sent to your Masked Phone while making sure your real phone number is not disclosed, first type the last four digits of the number that has just texted you, followed by a colon, followed by the message that you want the recipient to receive.
For example, if you receive a text from a phone number (123) 456 - 7891, in order to respond with a Masked text message, you would write "7891: (your message here)."