Personal Phone, Corporate Exchange Email— privacy

They do not have any access to any data on your device other than the contents of your Exchange account, which they have access to anyway.

They can set policies requiring passcodes, encrypted backups, restricting lockouts, disabling cameras, etc. They can also remotely erase your entire phone, including all of your personal data.

If you simply sign in to your exchange account, they have no access to your device. The only thing they could force is a passcode requirement.