ABAP contains a series of statements for processing character fields (types C, D, N, and T). There is no type conversion in these operations. The statements treat all fields as though they were type C fields, regardless of their actual types. The internal form of type D, N, and T fields is the same as for type C fields. For this reason, you can use these statements for all character-type fields.
Shifting Field Contents Replacing Field Contents Converting to Upper or Lower Case or Replacing Characters Converting into a Sortable Format Overlaying Strings Finding Strings Condensing Field Contents Finding out the Length of a Character String Concatenating Strings Splitting StringsThere is also a variant of the MOVE statement that only works with strings:
Assigning Parts of Character Strings.