You can create a form using the form_tag helper

<%= form_tag do %>
  Form contents
<% end %>

This creates the following HTML

<form accept-charset="UTF-8" action="/" method="post">
  <input name="utf8" type="hidden" value="&#x2713;" />
  <input name="authenticity_token" type="hidden" value="J7CBxfHalt49OSHp27hblqK20c9PgwJ108nDHX/8Cts=" />
  Form contents
</form>

This form tag has created a hidden input field. This is necessary, because forms cannot be successfully submitted without it.

The second input field, named authenticity_token adds protection against cross-site request forgery.

To create a search form, enter the following code

<%= form_tag("/search", method: "get") do %>
  <%= label_tag(:q, "Search for:") %>
  <%= text_field_tag(:q) %>
  <%= submit_tag("Search") %>
<% end %>

• form_tag: This is the default helper for creating a form. It's first parameter, /search is the action and the second parameter specifies the HTTP method. For search forms, it is important to always use the method get
• label_tag: This helper creates an html <label> tag.
• text_field_tag: This will create an input element with type text
• submit_tag: This creates an input element with type submit

Checkboxes

<%= check_box_tag(:pet_dog) %>
<%= label_tag(:pet_dog, "I own a dog") %>
<%= check_box_tag(:pet_cat) %>
<%= label_tag(:pet_cat, "I own a cat") %>

This will generate the following html

<input id="pet_dog" name="pet_dog" type="checkbox" value="1" />
<label for="pet_dog">I own a dog</label>
<input id="pet_cat" name="pet_cat" type="checkbox" value="1" />
<label for="pet_cat">I own a cat</label>

Radio Buttons

<%= radio_button_tag(:age, "child") %>
<%= label_tag(:age_child, "I am younger than 18") %>
<%= radio_button_tag(:age, "adult") %>
<%= label_tag(:age_adult, "I'm over 18") %>

This generates the following HTML

<input id="age_child" name="age" type="radio" value="child" />
<label for="age_child">I am younger than 18</label>
<input id="age_adult" name="age" type="radio" value="adult" />
<label for="age_adult">I'm over 18</label>

Text Area

To create a larger text box, it is recommended to use the text_area_tag

<%= text_area_tag(:message, "This is a longer text field", size: "25x6") %>

This will create the following HTML

<textarea id="message" name="message" cols="25" rows="6">This is a longer text field</textarea>

Number Field

This will create an input<type="number"> element

<%= number_field :product, :rating %>

To specify a range of values, we can use the in: option

<%= number_field :product, :rating, in: 1..10 %>

Password Field

Sometimes you want the characters typed by the user to be masked. This will generate an <input type="password">

<%= password_field_tag(:password) %>

Email Field

This will create an <input type="email">

<%= email_field(:user, :email) %>

Telephone Field

This will create an <input type="tel">.

<%= telephone_field :user, :phone %>

Date Helpers

• input[type="date"]

  <%= date_field(:user, :reservation) %>
  

• input[type="week"]

   <%= week_field(:user, :reservation) %>
  

• input[type="year"]

   <%= year_field(:user, :reservation) %>
  

• input[type="time"]

   <%= time_field(:user, :check_in) %>
  

Standard example: @models = Model.all select_tag "models", options_from_collection_for_select(@models, "id", "name"), {}

This will generate the following HTML: David

The last argument are options, which accepts the following: { multiple: false, disabled: false, include_blank: false, prompt: false }

More examples can be found: http://apidock.com/rails/ActionView/Helpers/FormTagHelper/select_tag