CSV is a family of conventions
Comma-separated is common, but locales that use comma decimals often prefer semicolons. Tabs and pipes are also used. The delimiter inside quoted text is data, not a column boundary.
For example, name,city followed by "Ng, Sam",Sydney contains two fields, not three.
Use UTF-8 for international text
UTF-8 represents Zoë, Montréal and 日本 without selecting a regional code page. A byte-order mark can help some spreadsheet applications recognise UTF-8, though modern import tools should let you choose it explicitly.
Diagnose a one-column file
If every row appears in one column, the importer chose the wrong delimiter. Open the file in a plain-text editor, identify the unquoted separator and select it explicitly rather than changing the data blindly.
Treat formula-like values carefully
Spreadsheet programs may execute fields beginning with =, +, - or @. This site neutralises those values when creating spreadsheet-friendly output. That protection can add a leading apostrophe, which is preferable to silently executing imported text.
Use the relevant tools
These guides are general information, not legal, security or records-management advice. Follow your organisation’s policies for sensitive files.