Right-click on the row number or column number and select [Resize row] or [Resize column]. Enter a new height or width in the window that appears.
Note that the display is different if you have a range selected. If you select multiple columns/rows by dragging, you can set them all at once.
- https://support.google.com/docs/answer/54813?co=GENIE.Platform%3DDesktop&hl=ja
- http://www.appsupport.jp/docs/spreadsheet-cellsize/
I remember having to research the same thing in Excel. Google Spreadsheets has less information available, so research is also difficult
- GAS
// autoResizeColumn
var ss = SpreadsheetApp.getActiveSpreadsheet();
var sheet = ss.getSheets()[0];
sheet.getRange('a1').setValue('Whenever it is a damp, drizzly November in my soul...');
// Sets the first column to a width which fits the text
sheet.autoResizeColumn(1);