When you write an excel formula, you always need to use excel functions in the formula. But there are hundreds of excel functions, how to select which one to use? how to insert function in excel formula? This article will tell you how to do it.

### 1. How To Insert Function In Excel.

#### 1.1 Insert Function In Excel Formula Manually.

- You can insert functions in excel formulas easily by hand.
- Select a cell and type the equal character (
**=**). - And then type the excel function name and parameters after the
**=**character. - For example, cell
**A1**contains the number**1**, cell**A2**contains the number**2**. - We want to use a formula to calculate the value of
**1 + 2**, then we can insert the formula**=A1+A2**in cell**A3**, and it displays the number**3**in cell**A3.** - We can also use the excel
**SUM**function to achieve the same goal. - Input the formula
**=SUM(A1, A2)**in cell**A3**, it will also display the number**3**in cell**A3**. - It will prompt some function tips during your input process.

#### 1.2 Insert Function In Excel With Insert Function Dialog.

- Excel provides hundreds of built-in functions, and each function has a dedicated purpose.
- If you forget the function name or want to explore all the built-in functions that excel provide, you can use the excel
**Insert Function**dialog. - In the excel
**Insert Function**dialog, you can browse all the excel built-in functions and the description of the function and its parameters. - Click the excel
**Formula**tab —>**Insert Function**item in the**Function Library**group. - Then it will pop up the
**Insert Function**dialog window, type the function name keyword in the**Search for a function**text box. - Then click the
**Go**button, and it will list the searched-out function names in the**Select a function**list box. - For example, if we search the keyword
**SUM**and click the**Go**button, then it will list all the excel built-in functions that function name contains the keyword**SUM**. - Click the function
**SUM**in the list, then we can see the function and it’s parameters description at the bottom of the dialog. - Click the link
**Help on this function**, then it will open a web browser and display the function detailed explanation web page in it. - Click the
**OK**button, it will go to the second dialog window with the title**Function Arguments.** - You can input the arguments that will be used in this function in this dialog. You can find the function arguments description in this dialog also.
- Click the
**OK**button, then it will close the dialog and apply the function with the arguments you input to the cell formula. - When you select the cell, you can see and edit the cell-contained formula in the excel top area
**Formula Bar**input text box. - There is a shortcut button
**fx**before the**Formula Bar**input text box. - When you click this
**fx**button, it will pop up the**Function Arguments**dialog window. - You can edit the function arguments in that window.