Logical functions return TRUE or FALSE and are sometimes called Boolean functions.
Here is an introduction to how to use Boolean functions in Excel. TRUE/FALSE functions
The IF() function is used to create formulas that depend on a boolean outcome. Using IF() to control calculations
Errors can occur in formulas (such as division by zero). Excel provides a function that will give an alternative outcome (such as blank or zero) if an error occurs in a formula. IFERROR function