iMessages from iPhone are not appearing on my iPad

You have said two very different things. We cannot tell which is your issue.

• Your post's header: "iMessages from iPhone are not appearing ..."
• Your post's body: "My messages from my phone are ..."

iMessages are one type of message. SMS text messages are another.

Check the section in this link on Text Messages using Continuity Services.

Use Continuity to connect your Mac, iPhone, iPad, iPod touch, and Apple Watch - Apple Support