If you are experiencing this error, you will notice that when you try to send text messages to someone who also has an iPhone, the text appears as an iMessage and it is sent from your email address, instead of your phone number. It shows the Apple account that is registered under iCloud and iMesage with email address. In order to get the issue resolved to make sure that the iMessage is sent from the phone number rather than the email, you can follow the below instructions.
Simply disable iMessage and then re-enable it.
Go to Settings, then Messages and select Receive At. Sign out from your Apple ID, turn iMessage Off and then On. Once you sign out, “Receive At” shoudl show as Use your Apple ID for iMessage.
Go to Settings, then Messages and select Receive at. Then choose Caller ID and tap on the mobile number.
Go to Settings and then select iMessage settings, then iMessage and finally Send & Receive.
Your phone number should be listed in grey with one or additional email addresses below. If there are phone numbers with a check mark next to them, click the phone number to remove the cehck mark from the listed email address.
On Mac, go to Messages, then Preferences, followed by Accounts and then iMessage. Unmark all the email addresses and leave the phone number only.
Go to Settings, then Messages, followed by Send & receive. Select Start New Conversation From and choose the phone number instead of the email address.
Go to your Apple ID account and check that the phone number is verified. Then check that the phone number is listed under mobile number. If that is not the case, add the mobile to your Apple ID account.
Another option that you can try is to open the Message app on your Mac and log into it. Then send the message from Mac.
Sign out from your Apple account and disable iMessage. Then turn iMessage on again and log into your Apple account. Once iMessage is on, you will get the option to receive as. Unmark the email address.
Sign out of all Apple account. Disable your phone, allow 10 seconds and then turn it on.