Hi sureshpathirana8,
It sounds like your messages aren't being forwarded to your iPad. We're glad you've joined us in Apple Support Communities. Let's see if this helps.
Let's double-check that this feature is still set up. Follow the steps in "Set up text message forwarding" in How to forward SMS/MMS text messages from your iPhone to your iPad, iPod touch or Mac. Please note the advice in: "Don't see the Text Message Forwarding setting on your iPhone? Go to Settings > Messages, turn off iMessage, turn it back on, tap Send & Receive, tap Use Your Apple ID for iMessage, then sign in with the same Apple ID used on your other devices."
If you review the above information and the issue remains, have you had a chance to restart and check your iPad for updates? Both restarts and updates resolve issues both big and small.
If the issue remains after following those steps, let us know what steps you had a chance to try from above.
We hope that helps with your question and take