Color Hack Highlights Certain Contacts in Your iPhone’s Mail App

A little-known setting on your iPhone gives you the ability to change the color of certain contact names and email addresses when composing an email. The color setting works well for visually separating contacts at a glance, and can even help you send an email to the wrong person.

Imagine you send a critical professional email to a colleague’s personal email account instead of a work one, and then that person never opens it. Worse, you could accidentally email a password or other sensitive information to a contact with the same name as the one you really wanted to target.

If you have contacts with multiple email addresses, or contacts with similar names, it’s easy to make the mistake of sending an email to the wrong person, account, or domain. You may even have multiple email accounts set up in Mail, where you can choose the wrong one. The Flag Addresses option in Mail helps you see who you’re sending messages to, and from, with no extra effort.

Using Mark Addresses to Red Flag Email Domains

The ability to tag addresses in the Mail app for iOS and iPadOS is one of Apple’s hidden gems. You can activate it by going to Settings -> Mail -> Mark Addresses and entering the domain or list of domains separated by commas. These are the domains you don’t want to tag.

As soon as you start composing a new email and enter the recipient’s email address in the “To”field, you will notice that the application colors it blue or red. The blue emails come from the safe domains you added, while the red emails are flagged because you didn’t include their domains. This gives you the ability to quickly check if you’re sending a message to the correct domain or not – good fail-safe if you don’t see a contact’s profile picture when you add them.

Marked addresses can be handy in many situations, but they are necessary when sending sensitive data that shouldn’t be sent to the wrong address. Even if you don’t have sensitive data to send, you can use this feature to color-code emails from a work or school domain to distinguish them from everything else.

Mail will also flag the address you’re sending from if it doesn’t belong to one of your safe domains. The only difference in the “From”field is that approved domains are not highlighted in blue. Instead, they remain white or black text, depending on whether you’re in light or dark mode.

Once you set up the desired domains, Mail will only remember them on that particular device. The changes won’t sync across your other iCloud-connected devices, so be sure to apply them on any devices you want.

Marking addresses in Mail is not a new feature. If you’ve never heard of it, you might be surprised to know that it’s been around since iOS 8 in 2014.