You need to write a drop-down list, so that the user can mark several values.
<select multiple="multiple" id="admission" name="admission[]" id="select" class="select"> <option disabled>Выберите</option> <option value="XXX1">XXX1</option> <option value="XXX2">XXX2</option> <option value="XXX3">XXX3</option> <option value="XXX4">XXX4</option> </select> Such a solution only works if you hold down the ctrl / shift keys, this is not very convenient. Is there a solution so that you can simply click on the items in the list and these values remain selected? Or make a drop-down list where items can be ticked.