Leaving your ballot paper blank
Blank ballot papers are counted, but they have no influence on the outcome of a vote.
You can leave your ballot paper as it is, without writing anything on it. Blank ballot papers are counted, and their number is announced separately and used to calculate the voter turnout for federal votes.
Influence of blank ballot papers on the outcome of a vote
Blank ballot papers do not determine the positive or negative outcome of a vote. If you cast a blank ballot, you leave it up to other voters to decide whether a proposal is accepted or rejected.