my Apple Watch is texting off of my email instead of my phone number. I do get the alerts on my watch, but then I go to messages on my watch and it is not there. And if I start a conversation on my watch it pops up as my email on their phones.
Apple Watch Series 3, watchOS 5
Go to Settings > Messages > Send & Receive to change which phone numbers and email addresses are tied to your iMessage account. ... Power on then iPhone and and re-enable iMessage by going to Settings > Messages and turning the iMessage switch to the on position
I think you are talking about the Messages app, using iMessage (blue bubbles) rather than pure traditional SMS text messages (green bubbles) - not that it really matters for this problem.
Messaging on your watch mirrors its settings from your iPhone, so you need to check on the iPhone, Settings / Messages / Send &Receive, see which addresses exist there and which is checked as the default. Ideally you want at least your Apple ID and the phone number for receiving, but it is then your choice which is used by default for sending new messages.
Apple Watch texting
