How to use checkbox in ruby on rails

Have you read this?

http://apidock.com/rails/v4.0.2/ActionView/Helpers/FormTagHelper/check_box_tag

Either you use the check_box_tag or the f.check_box inside a form builder, plus you have to add a label to display it. The construct you are using just generate the <input type="checkbox" value="something" /> and not the label, that you have to add, just like text or with a <%= label_tag 'whatever' %>.

try the below code

<%= check_box :monday, {:class => "anyclass", :style => "anystyle"}, "monday" %>

one way to do is

<%= check_box_tag "Monday", 'yes', id:"monday" %> Monday

or u can do this also

 <%= check_box_tag "Monday", "yes" %>
 <%= label_tag "Monday" %>

You need to use a label:

<%= form_tag your_path do %>
    <%= label "Day" %>
    <%= check_box "Monday", "yes" %>
<% end %>