Office 365 (Outlook 2016/Outlook on the Web) - Learn about junk email and phishing
Mail identified as possible junk email is automatically moved to the Junk Email folder, and any potentially dangerous content within the message, for example, links or executable code, is disabled.
When you receive a message that might be junk email, it will be moved to your Junk Email folder. You can treat messages in your Junk Email folder like any other message. If a message in your Junk Email folder is one that you want to keep, click the extended menu in the reading pane and select mark as not junk. The message will be moved to your Inbox and the sender will automatically be added to your Safe senders and recipients list.
Junk email, also known as spam, is unsolicited email - usually commercial. It can strain networks, clog email servers, and fill mailboxes with unwanted and possibly offensive messages and images. Most of it is annoying, but harmless. Most junk email will be blocked by the email server that hosts your account.
Phishing is a specific kind of junk email that's used to obtain private information for use in identity theft and other scams. The email message appears to come from a trusted source, such as your bank, and often includes the actual business logo and an apparently legitimate reply address.
In the Outlook client, right click on the email, hover over Move and select Junk Email.