E-mail security is foremost important for any Organization and having a strong Anti-Spam, Anti-Spoofing, Anti-Malware and Anti-Phishing solution to provide this functionality is quite challenging, When it comes to Office 365, you have the power of Exchange Online Protection (EOP) that get these challenges addressed, Microsoft team has brought lot of innovations in this space and now they started to roll-out Safety Tips in Exchange Online Protection, an additional layer of protection for all users that provides a warning to the user in an email that is marked suspicious, or a reassurance when a message is safe.
More information is available in the Official Blog post here: Email Safety Tips in Office 365
Believe most of you are aware about the latest Anti-Spoofing Protection capabilities added to EOP, called Exact Domain Spear Phishing Protection (name subject to change) this helps in detection of spoofing for your domain even without the standard SPF, DKIM, or DMARC records.
Read the below Blog from Terry Zink MSFT,
To read the below TechNet Documentation to know about Anti-Spam and Anti-Malware support with EOP.
Add-on Support Article,
Read the More Information Section in the article for related content.
For Enhanced Security and advanced protection of your E-mail environment use Exchange Online Advanced Threat Protection
Know more here: Exchange Online Advanced Threat Protection Service Description
Ensure that you know and utilize all of these resources to provide a safe E-mail environment.