Make field MPN material in source list editable

Dears,

In table EORD, there is field MPN material(EMATN), and also in below link:

https://answers.sap.com/questions/11983519/source-list-with-mpns.html

I find there is such field which allow user to edit it in ME01.

While in my system(S/4HANA 1809), there isource-list.pngs no such field in ME01.

MPN is activated in our system(OMT0 is set up, AMPL is activated).Can anyone help to guide how to make it editable in ME01 for us? I haven’t find any place for configuration.

Thanks.

For more detail with screenshot, pls kindly refer to attached file.