MSIT_CNVIDBASIC is a standard SAP Structure so does not store data like a database table does. It can be used to define the fields of other actual tables or to process "Material Number Conversion: General Data" Information within sap ABAP programs. This is done by declaring abap internal tables, work areas or database tables based on this Structure. These can then be used to store and process the required data appropriately. i.e. DATA: wa_MSIT_CNVIDBASIC TYPE MSIT_CNVIDBASIC.
The MSIT_CNVIDBASIC table consists of various fields, each holding specific information or linking keys about Material Number Conversion: General Data data available in SAP. These include MANDT (Client), CONVID (Key for Table TMATCONV), LMATNR (Length of the material number), LMASKE (Length of the template for converting material numbers)... See below for full list along with technical details, documentation, text table, check tables, foreign key relationships, conversion routines, relevant tcodes and example ABAP select code etc. .