How to only format 20 columns on spreadsheet

I am on spreadsheet and am unable to find how to create only a small number of columns.

Really??? this is beyond so unhelpful

What do you mean?

Seems that was an unhelpful comment masqueraded as an answer which it was not.

Just use only the columns you want to use. Empty columns are also not stored in a document so don’t take space if that concerns you. If you want to make the sheet appear as if it had no further columns then hide the excess columns, i.e. select the columns, then on a selected column header invoke the right click context menu, choose Hide Columns.