Explanation
A goods issue posting to a production order allocates actual costs to the production order and reduces the inventory of the issued materials. A goods issue can be posted as a backflush, which means that the system automatically issues the components that are required for production based on the bill of material (BOM) and the quantity produced. References: SAP S/4HANA Sourcing and Procurement | SAP Learning, Course S4510, Unit 3, Lesson 1.

Explanation
During reorder point planning, the system performs a net requirement calculation for every material included in the planning run and carries out a lot-size calculation for every material with net requirements. The system does not flag materials that have been subject to an activity relevant to MRP or perform backward scheduling to determine the availability dates of purchase requisitions2 References: SAP Help Portal - Reorder Point Planning

Explanation
When setting up a cross-company-code purchasing organization, you do not need to maintain the assignment of plant to purchasing group. A purchasing group is an organizational unit that is responsible for the day-to-day purchasing activities for one or more materials or services. A purchasing group can be assigned to one or more plants, but it is not mandatory. References: SAP S/4HANA Sourcing and Procurement | SAP Learning, Course S4500, Unit 1, Lesson 1.

Explanation
A movement type is a key that determines how goods movements are updated in inventory management and accounting. When defining a new movement type, you can configure some of the following aspects:
The value string for account determination, which means that you can define which accounts are posted during the goods movement based on the valuation area, valuation class, account category reference, transaction/event key, etc.
The allowed transactions, which means that you can define which transactions (such as goods receipt, goods issue, transfer posting, etc.) are possible with the movement type.
The field control, which means that you can define which fields are mandatory, optional, or hidden in the material document for the movement type. References: [SAP Help Portal], [SAP Help Portal], [SAP Help Portal]

Explanation
You can create MRP areas to plan materials differently within a plant. An MRP area is an organizational unit that represents a separate area of material requirements planning within a plant. You can use MRP areas to plan materials according to different criteria such as storage location, subcontractor, or sales area. References:
[SAP S/4HANA Sourcing and Procurement | SAP Learning], Course S4525, Unit 1, Lesson 1.