What is the function of the insertion?

If you mean inserting columns, you can insert new columns into a worksheet, like when you may need a new column in the middle of existing ones. The Insert Function, allows you to insert new functions in a cell. The Insert key can change between Insert mode and Overtype mode, allowing you to change what happens when text is typed into existing text. In Insert mode, existing text is pushed to the right by the new text. Overtype mode replaces existing text as you type. The Insert tab on the ribbon allows you to insert lots of things, like charts or objects.