Why don’t my emails appear on my iPad but do appear on my phone?

Hi, have you setup your email account on your iPad? If not go to Settings > Mail > Accounts > Add Account . Fill in your account details and you should have your account now setup on your iPad. This is Apple’s support page https://support.apple.com/en-us/HT201320

Is the email account set up on both devices?

If yes, then is the account using pop or imap as the incoming server?

Is there any error message on the device which cannot download emails?