Operations In INTERNAL TABLE : 

1. Pushing the data from work area to internal table by using there keywords APPEND,INSERT and COLLECT.
2. Reading the data from internal table is two types.

•  single record : by using READ keyword we read the singe record from internal  table.
• Multiple records : bu using LOOP AT key word we read the multiple records from internal table to work area.

     3. Modify the data in an internal table by using MODIFY keyword.

     4. Delete the data in internal table by using 'DELETE' keyword.

     5. Sort the data in an internal table by using SORT keyword. 

APPEND :-

Append is a keyword which is used to move or transfers the data from work area to internal table.

syntax :- APPEND  <WORK AREA > TO <INTERNAL TABLE>.

Ex :-  APPEND WA_T001 TO IT_T001.

INSERT :-

Insert is a key word which is used to transfer the data from work area to internal table based on the Key-word.

syntax :- INSERT <WORK-AREA > TO <INTERNAL TABLE>
Ex :- INSERT WA_T001 TO IT_T001.