How to find a description of a calc function fast by its name?

Would be great.

Does not the online help do this for you? Press F1 to open the help, and search for the function you want.

Or, click on the Function Wizard (fx) to the left of the data entry box.

Or, from the menu Insert | Function will also bring up the function wizard.

If you are new to LibreOffice, you may find the online LibreOffice Help useful. There is a list of functions there also.

If this answer helped you, please accept it by clicking the check mark :heavy_check_mark: to the left and, karma permitting, upvote it. If this resolves your problem, close the question, that will help other people with the same question.