If you want to display a text field of more than 255 character to an input enable field on screen, forget it, it's not possible (try with SE51 you will get an error as maximum size reached, 132 max).
You can define a long field in database, a big character field or (at end of table) a LCHR or LRAW type, remember that
- A table may not have more than 249 fields. The sum of all field lengths is limited to 1962 (whereby fields with data type LRAW and LCHR are not counted).
- Fields of types LRAW or LCHR must be at the end of the table. Only one such field is allowed per table. There must also be a field of type INT2 directly in front of such a field. The actual length of the field can be entered there by the database interface.
So better use an INT2 ajd, a LCHR at end of your table, and maintain those with cl_gui_textedit as suggested by