Studio Transaction automatically maps long text fields, but the mapping differs depending on the recording mode you used.
Non-Batch Input mode or Standard mode: All the long text recorded in a field is assigned to one column with the label Long text. You can directly upload the Excel cell values without breaking the text.
Batch Input mode: For Batch Input mode recordings, first break your text into several lines with each line being 72 characters or less in length. Each line of long text recorded in the SAP editor is assigned a separate field in the mapper, and is mapped to a different column in the data file with a number and the label Text editor text line. (Ensure you use a separate column in the Excel worksheet for each line of long text; if you place all the long text in one column, the error "Text longer than field" appears.)