Ever send an email to someone, only to find out the wrong name is showing on it? When you send an email to another person, the name that shows on the account is called the Sending Name. This is different than an account's Display Name or Nickname, which shows in the top right part of the screen when you're signed in.
The Sending Name for the account can only be changed from the desktop web version of Yahoo Mail, and not from a mobile device. Follow these steps below to change it.
Mouse over the Settings menu icon (Gear) | select Settings.
Click on the Yahoo email account.
Enter a new name in the "Your Name" field.
Keep in mind that other apps may have their own settings for your Sending Name such as the default Mail app on an iPhone or Android. Whatever is in place there will override what's set up on the Yahoo account. If the wrong name appears on your emails after following the steps above, double-check the settings in the app you're using.