How to create a "Mail User" that is synced from Active Directory (ADSync) (Mail Enabled Object) in Office 365

Creating Mail-Enabled Objects-

Filter: objectClass = user & objectClass = contact

Mandatory Attributes:
mailNickname: This attribute is the alias to the mailbox.

displayName: This attribute is the text that is the readable name that represents you for mail delivery, and also in the address book.

targetAddress: This attribute is the e-mail address to which you want to redirect the mail. This attribute is formatted like the proxyAddresses attribute, where there is a prefix that defines the address type, for example, "SMTP:gyip@microsoft.com".