SEARCHTAB is an SAP Structure so does not store data like a database table does but can be used to process "Internal Admin. of the Search Screen Structure" 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_SEARCHTAB TYPE SEARCHTAB .
Below is the documentation avaialable and full details of the fields which make up this Structure.
|Data Type||length (Decimals)||Check table||Description||Conversion Routine|
|LFD||DOKU_LFD||CHAR||2||Sequence number for search tab|
|MODE||DOKU_MOD||CHAR||1||Output control for search dynpro|
|OPERATOR||DOKU_OP||CHAR||10||Logical operator for the search screen|
|WORD||DOKU_STR||CHAR||60||Search expression for search screen|