Write an ABAP code to call an RFC function
Here is an example ABAP code to call an RFC function named `Z_MY_RFC_FUNCTION`:

    REPORT z_test_rfc.
    
    DATA: lt_return TYPE STANDARD TABLE OF bapiret2,
          ls_return LIKE LINE OF lt_return.
    
    DATA: lv_param1 TYPE string,
          lv_param2 TYPE string.
    
    lv_param1 = 'Parameter 1'.
    lv_param2 = 'Parameter 2'.
    
    CALL FUNCTION 'Z_MY_RFC_FUNCTION'
      DESTINATION 'MY_DESTINATION'
      EXPORTING
        param1 = lv_param1
        param2 = lv_param2
      TABLES
        return = lt_return.

    LOOP AT lt_return INTO ls_return.
     WRITE: / ls_return-type, ls_return-message.
    ENDLOOP.

In this code, we first declare some variables for storing input parameters and output data. Then, we set the input parameters `param1` and `param2` to some sample values.

Next, we call the RFC function `Z_MY_RFC_FUNCTION` using the `CALL FUNCTION` statement. We specify the destination `MY_DESTINATION`, which is the logical destination that points to the system where the RFC function is defined.

We pass the input parameters `param1` and `param2` using the `EXPORTING` clause. We also specify the return table parameter to retrieve any output data from the RFC function.

Finally, we loop through the `lt_return` table to display the results of the RFC call. The `ls_return-type` and `ls_return-message` fields contain information about any errors or warnings that may have occurred during the call.
Can you tell me more about ABAP and where it is used?
ABAP (Advanced Business Application Programming) is a high-level programming language used for developing applications in the SAP (Systems, Applications, and Products in Data Processing) environment. It is primarily used to develop applications and reports for the SAP R/3 system, which is an enterprise resource planning (ERP) software system used by businesses to manage financials, logistics, and other business processes.

ABAP is a procedural language and is designed to be easy to learn and understand for developers with a background in other programming languages like C or COBOL. It has a rich set of built-in functions and data types for working with SAP data, as well as extensive support for database access and manipulation.

ABAP is used to develop a wide range of SAP applications, including custom reports, workflows, forms, interfaces, and extensions to standard SAP functionality. It is also used to develop applications for SAP's cloud platform, SAP HANA.

In addition to its use within the SAP ecosystem, ABAP has also been extended to support web development using ABAP Web Dynpro and SAPUI5, which is a framework for developing web applications that run on SAP's Fiori platform.

Overall, ABAP is an important language for businesses that rely on SAP for managing their operations and require custom development to meet specific business needs.