Q: how to assigne a unique sound to a single incoming e mail address and have it aleart when in lock screen 4s Iphone 6.13

Sorry, no way to do this with an iPhone.

See if this will do what you want:

http://support.apple.com/kb/HT5463

I have email messages alert sounds turned off except for VIP addresses (of which I have only one). That means I only get alerted for that one address.

To add a Contacts entry to VIP senders in iPhone Mail:

• Open your list of mailboxes in iPhone Mail.
• Tap the > button next to VIP.
• Select Add VIP… at the list's end.
• Tap the desired entry from your contacts.

Then, in Notifications>Mail, turn off the souds for your email account but enable them for VIP.

Note that all VIP emails will have the same tone. It's more like the Priority feature on a BB than custom text tones.

Best of luck.

If that doesn't work for you and you have Gmail, take a look at ifttt.com. It will allow you to set up an SMS alert for specific email addresses (and can do about a million other things as well). However, it only checks every 15 minutes.

I'm glad it helped!