WorldPosta Incredible gives you the ability to search not only inside the messages but also inside the attachments.
1. Locate the search bar at the top of the messages panel.
2. Enter your search criteria, such as contacts, part of the message
3. Click Enter or click on the search icon.
All messages matching your search terms appear in the search results.
Note: Incredible search isn’t case sensitive, searching for “JOHN” is the same as searching for “john”.
When you type the search criteria and show your results, you can specify further search criteria. Such as, search entire mailbox, current folder, or current folder and subfolders.
Also, you can specify the time frame for the messages, (older than a week, older than a month, older than a year)
You can also sort the search results, by choosing from the menu under it.