Tcodes - MM

MB51 - Material document list (we can also see ‘booked in history’ )

MIGO – Goods receipt – book in

MR21 – To set MAP manually

MR51 - To check FI docs for Material documents (useful for MAP value understanding)

MB1A - Enter Goods Issue (Can be used to create Stock - For testing, use 551/552 postings - for removal/create stock in Plant-storloc)

MRBR - Vendor Invoice verification - Check and Release block - u can find blocking reason here

MD04 – Stock flow

CO09 – Availability overview for material

Difference between CO09, MD04 and MMBE – below link

https://scn.sap.com/thread/1449072

In CO09, click on 'Overview Stock' button to give a highlevel over view, From this drill down by Stor Loc, this gives a clear picture..

CO06 - Backorder Processing - Here, you can remove confirmed qty (of undelivered orders) and give it to another one.

MD04 also contains Forecasting values - so little confusing
 

ME59N – Automatic creation of POs from PR

ME29N – Realease PO

MEAN - To create an independent address (with address number) which can be used as 'Delivery address' in PO (manually give address number)

ME51N – Create Purchase requisition

ME21N – Create PO

MMRV – To check Open posting period (material master)

MMPV – To close existing period and open next one (material master)
MMPI - To open previous periods

M_LD – Purchasing condition records report

MR51  -  Accounting documents for material -  we can see MAP changes here

MIR4 -  Vendor invoice display
MIR5 - Vendor invoice report

MEK1 - Create Pricing condition -for POs

V_V2 - Rescheduling Sales and Stock transfer docs - by material
OPPJ - ATP check rules

ME2M, ME2L - Purchase orders based on Material and Vendor respectively
ME1M, ME1L - Purch Info records based on Material and Vendor respectively