Cheat Engine

[navarone]

So whenever I search for a text within game the result appears in this box,
modifying the text in result will also appear on game



What does this box contain exactly? The one under the disassembler?

Also how do I find what piece of code accesses this string?

[Geri]

That box is the hexview. You can see the content of the memory as in hex editors.

If You want to see what is accessing to the string, use the find out what... stuff or set a data breakpoint.
You can also use View->Referenced strings (but that will not show all strings)