A spreadsheet of places with latitude and longitude columns becomes a map layer once it is GeoJSON, which web maps and GIS tools read. Each row becomes a point with its other columns as properties.
Every format is read into plain GeoJSON features and written out from there, so coordinates, names and properties carry over wherever the target has a place for them. The first row must name a latitude and a longitude column (lat, latitude, lon, lng, longitude and similar); name, elevation and time columns are recognised, and every other column becomes a property. A row with no valid coordinates stops the conversion and is named. Coordinates are written longitude first, then latitude, as GeoJSON requires. Coordinates outside the latitude and longitude range are refused, since the file is probably in a projected coordinate system.