@Html.TextBox("nomeTxt", null, new { @class = "form-control", @placeholder = "Exemplo de placeholder", @type = "text" })

@Html.TextBox("nomeTxt", null, new { @class = "form-control", @placeholder = "Exemplo de placeholder", @type = "text", @maxlength="10" })

<input id="txtData" name="txtData" placeholder="Ex.: 13/10/2019" data-date-format="dd/mm/yyyy" maxlength="10">