How To Do Implicit Enhancement

Enhancement options are positions where we can add our code, SAP has provides with these positions where we can put our code as per the requirement, we can add an implementation element without modifying the original code of SAP.
Enhancement implantation elements are stored in the package with own transport objects thus avoiding any conflict in modification in later stages.
 Explicit and Implicit Enhancement Options
 Implicit Enhancement options are for free, provided by the framework, while the explicit ones need to be inserted explicitly, as the name indicates.
How To Do Implicit Enhancement
Suppose we want to enhance Fun Mod:
We know Fun Mod 'popup_to_inform' is used to display popup message, I will add one more Fun Mod 'popup_to_confirm'.
And on selecting cancel the program should exit.
1.In SE37.

 2. Screen will look something like this.

 3. Select enhance source code  

 4.Screen will come white & fonts will come Gray, select show_implicit enhancement options.

5. Yellow lines will come, place your cursor on yellow strip & create enhancement.

6. Choose declaration type of enhancement.
7. Now place your required code in this section.

8. Here we have placed one popup to confirm

9. Activate the function module & run you will find the implemented enhancements.