Understand CSV and XLSX
CSV is delimited plain text; XLSX is a structured OOXML workbook. Conversion packages parsed rows into real spreadsheet cells without changing the source file.
Choose the correct delimiter
Use automatic detection or explicitly select comma, semicolon, tab, or pipe. Quoted delimiters, escaped quotes, empty fields, Unicode, and multiline cells follow the shared bounded CSV parser.
Preserve values as text
The default does not infer numbers or dates, so ZIP codes, long identifiers, leading zeros, and date-like strings remain as supplied.
Prevent formula injection
A value beginning with equals, plus, minus, or at-sign is stored safely as visible text rather than becoming an executable spreadsheet formula.
Review the workbook
The workbook contains one worksheet with editable cells. Add spreadsheet-specific types, formulas, and formatting explicitly in Excel only after reviewing the preserved source values.