Final Answer

To create an absolute reference in spreadsheet applications like Microsoft Excel or Google Sheets, you need to use the dollar sign character, $.

Explanation:

An absolute reference is used when you want a reference to a specific cell to remain constant even if you copy the formula to another location. The dollar sign is placed before both the column letter and the row number to create a reference like $A$1. This ensures that if the formula is copied to another cell, it will still refer to cell A1, rather than changing to another cell reference relative to its new position. The use of $ allows for precise control over cell references in your calculations. Other characters such as # and X do not have this functionality in spreadsheet software.