There are several answers to your questions:
You have asked if someone can do something bad knowing the IP address and other info in the link. (Your link uses an IP address, and the full path of the PHP file, and the idCode
parameter.) There is nothing implicitly insecure about using any of those things. However, whether or not someone is able to do something bad depends a great deal on the exact contents of the VerifyNewAccount.php
script and how idCode=someThing
are actually used. Having that info is not insecure all by itself, unless the script allows that information to be used improperly (the programming details are beyond the scope of this question, and would be more appropriate for another question based on the contents of your PHP script).
You have also asked if someone can "listen" on that address. No one can listen on that address simply by knowing what it is. However, this does not rule out the possibility of a man-in-the-middle-attack (again, the networking details are beyond the scope of this question, and would be more appropriate for another question based on your networking architecture).
Really, there is nothing you can possibly "hide" in this link that cannot be revealed using elementary networking tools. (In fact, you MUST have all the parts revealed or else your system could not be used at all.)
Considering your lack of knowledge, keep on asking questions like this, and keep on examining each and every part of your system as it is built. There is nothing magical about security, but you must keep on asking questions and examining and tightening weak points.