VB.NET How to Title Get Exe

For example, I opened "Untitled - Notepad" and I want to detect the title of it and pass the name processbyname to textbox1. How can I do it? So when "Untitled - Notepad" comes up and it is active, I want to transfer the name of processbyname to textbox1.

As soon as the "Untitled - Notepad" title comes up, I want it to automatically detect it and print it to textbox1 as a "notepad". So I want to processbyname.

Thank you.