... - any number of comma-separated formulas corresponding to format codes embedded in the format string
Notes
The string parameter can contain one or more embedded Format Specifiers. Each one will correspond to a parameter passed to the function. The corresponding parameter (formula) is evaluated and its result is inserted in the string in place of the format specifier.
An example this would be Format("5-day ROC {%2}", c / c[5] - 1).
Use {?} to insert a string within another string. The parameter that corresponds with {?} can be either a literal string or a function that returns a string. You can even write nested Format functions if you can think of a reason to do so.