You can't get someone else's text messages on your iPhone. You can however get iMessages from another iphone on your iphone. See this page to understand the difference between text messages and iMessages: Difference between iMessages and Text Messages
To get imessages from another iPhone on your iPhone, just add the other person's iCloud information (iCloud user name and iCloud Password) in your Messages settings on your iPhone. Be warned that doing this will send messages to every device using that iCloud account that your iPhone is now using that account.
1) get her iPhone and read them
2) If you restore her (or another) iphone from a backup made when those messages were on the phone, they would be in the Messages app
those are the only ways i know of.
The iCloud notificaiton only goes out the first time you add the icloud account to a device OR when you remove/re-add it to iCloud..
When properly configured, all iDevices will receive all iMessages.
If I want to read somebody imessages I add my icloud to there iphone am I right? Correct me if if Im wrong. Then When person receives an imessage it will show on my iphone too ? is it will show my imessages on his iphone then ??? if yes what can i do to dont get caught ???
Many thanks !
Yes, when you setup someone else's' iMessage on your iphone, all iMessages that you send are now as that person. See this video for a little more info: two iMessage accounts on your iPhone.
Also remember that when you setup your iPhone with a different account all other devices using that account will get a notification.
My momma always taught me that the best way to do something without getting caught is to not do anything wrong in the first place.
If these are text messages (green bubbles in the Messages app) then you will need to talk to your mobile/texting service provider to find out what's up.
If these are iMessages (blue bubbles in the Messages app) then both phones are sharing the same iCloud account - not usually a good idea unless it's the same person using both phones. Check in SETTINGS | Messages | Send & Receive to make sure each device is using it's own iCloud account, or remove the icloud account from one of the phones, or just turn-off iMessages for one/both of the phones.
More information about text formats