If I delete messages, does it also delete the messages on my IPhone?

If you are synchronising your iPad and iPhone Messages via iCloud, deletion of Messages on either device will delete the associated message on both devices.

Settings > [Your Name / AppleID] > iCloud > Messages

• If set to ON, the device is using Messages in iCloud; message deletion will occur on all devices that are using Messages in iCloud.

• If set to OFF, message deletion from the device will only delete the message on that device.

From this you should be able to see that you can disable Messages in iCloud for just one device - and not the other. In so doing you can keep a backup of your Messages in iCloud for one device - and still be able to delete messages on the other.

Hi, go to settings-yourname on the top, then scroll down and look for messages and toggle the switch to off. Do this on both devices. Now whatever you delete on your ipad will delete on your ipad and not your phone, but before you do this make sure you make a backup.