question about creating custom function in excel!

[siamandm]

Hello All,
when you type an excel function at the beginning it shows a small description about the function as below

01.png

and later it guide you what arguments you need in your function as blow

02.png

what are these called and how to add them to your custom user defined function?

[StuartR]

There's a helpful discussion about this topic on Stackoverflow: How to put a tooltip on a user-defined function

[BobH]

Thanks, Stuart.

I didn't know that it was possible for users to define functions. Do you have a reference I should read?

[HansV]

Create custom functions in Excel
How to Write User Defined Functions (UDFs) in Excel with VBA