The conducting and carrying on of all city elections shall be under the control of the mayor and council, and they shall, by ordinance, subject to the provisions of this Charter, provide for the holding of all municipal elections. Sample ballots and instructions to voters may be sent out to the registered electors entitled to a vote at any municipal election, but the sending out of said ballots and instructions shall not be necessary, and no notice of any such election, other than the publication of the ordinance calling and providing for the same, shall be necessary.