How do I transfer my notes from my phone to iPad?

That depends on how you are storing them on your iPhone.

If they are stored in the iCloud Folder in the Notes App, they automatically get synced to any device using the same apple ID for iCloud.

You can also store them in services like Gmail, Hotmail, or other 3rd party email accounts, and should sync if those same accounts are setup for Notes on the iPad.

You can tap on the "<" icon at the top left of the Notes App to see your folders.

You sync them to your iPhone from the same cloud account you're syncing them to on your phone.