Is there a way to view my old imessages now that I do not have an apple phone? If I sign in on an ipad can I view them or online?

IF you backed up the iPhone - you can try to restore that backup to the iPad

You will lose anything that is accumulated between the date of the restore and now

Other than that - no

If they are not on the iPad, then there is no place for you to view them. There is no place to login and view old iMessages. There is no place outside the device to archive them.