When a personnel number is rejected in the payroll run, the system sets the Payroll Correction indicator in infotype 0003 (Payroll Status) for that employee1.
When a personnel number is subject to master data changes in the correction phase, the system also sets the Payroll Correction indicator in infotype 0003 (Payroll Status) for that employee2.
The Payroll Correction indicator means that the payroll results of the employee need to be recalculated in the next payroll run3.
Therefore, the system uses the Payroll Correction indicator in infotype 0003 (Payroll Status) to identify the personnel numbers whose payroll results need to be recalculated in the next payroll run. References =
1: SAP Help Portal, Payroll Control Record, section "Rejected Personnel Numbers".
2: SAP Help Portal, Payroll Control Record, section "Master Data Changes in the Correction Phase".
3: SAP Help Portal, Payroll Control Record, section "Payroll Correction".
4: SAP Help Portal, [Payroll Control Record].

When you call up a main schema using transaction PE01, you have the following columns available in the editor:
Line: This column shows the line number of each entry in the schema. It is used to identify and navigate the schema entries.
Function: This column shows the name of the function that is executed by the payroll driver. A function can be a payroll operation, a personnel calculation rule, or a sub-schema. A function can have one or more parameters that define its behavior and output.
Parameter: This column shows the parameters that are passed to the function. Parameters can be constants, variables, or expressions that modify the function's logic or input.Parameters are separated by commas and enclosed in brackets.
Feature: This column shows the name of the feature that is used to determine the value of a parameter. A feature is a decision tree that evaluates certain conditions and returns a value based on the outcome.
Features are used to customize the payroll schema for different scenarios or requirements.
Return Code: This column shows the return code that is generated by the function. A return code is a numerical value that indicates the status or result of the function execution. Return codes can be used to control the flow of the schema or to trigger certain actions.
The columns B. Feature and D. Return Code are not always visible in the editor. They can be displayed or hidden by using the menu options View -> Feature or View -> Return Code. Therefore, they are not correct answers to the question.
References =
SAP Help Portal: Payroll Schema
SAP Community: Understanding functions in Payroll Schemas

The operation ADDWT is used to transfer wage types to an internal table. An internal table is a data structure that can store multiple records of the same type. The operation ADDWT can be used in personnel calculation rules (PCRs) or schemas to manipulate wage types. The syntax of the operation is:
ADDWT&XXXX
where XXXX is the four-digit wage type number. The operation will add the wage type XXXX to the internal table IT, which is a predefined table that contains all the wage types for the current payroll period. The operation will also perform some checks and validations, such as:
If the wage type XXXX does not exist in the payroll cluster, the operation will create it with the default attributes from the wage type table T511.
If the wage type XXXX already exists in the internal table IT, the operation will add the amount and number fields of the new wage type to the existing one, unless the wage type is cumulative or additive.
If the wage type XXXX is cumulative or additive, the operation will create a new line in the internal table IT with the same wage type number, but with a different line counter.
If the wage type XXXX has a time unit, the operation will convert the time unit to the payroll period unit, using the conversion factors from the table T510S.
The operation ADDWT can also be used with modifiers, such as:
N: to suppress the creation of a new wage type if it does not exist in the payroll cluster.
K: to keep the original attributes of the wage type from the payroll cluster, instead of using the default attributes from the wage type table T511.
A: to add the wage type to the internal table IT without any checks or validations.
References = Working with Simple Internal Tables, SAP C_HCMPAY2203 Exam Practice Test Instant Access - CertsHero