# Booking form
When a service is created, its reservation form by default contains the *Name*, *Email* and *Phone* fields, so those are the data required to the customer during the reservation process.
The service booking form is **fully configurable** thanks to a very powerful **form builder**.
## How to add a new field
Click on any label to the left of the form builder to add the corresponding form field.
At the moment, those are the available fields:
* Input text
* Checkbox
* Number
* Options (dropdown)
* File upload
* Paragraph (informative text, no input)
## How to add a validation rule to a text field
If you need to add a validation rule to a certain text field, you can do that by expanding the properties of the form field (clicking on the *caret* icon to the right) and then expanding the *Validation* section.
Adding a validation rule to a text field
A validation rule is a [Regex expression](https://regex101.com/). Under the Regex field you can find some buttons to add the most common Regex validation expressions. If you want to use a custom Regex expression, just write it in the field.
If a regex expression is provided, the booking form will display an error below the field if the data provided by customer doesn't pass the Regex validation.
{% hint style="info" %}
Please note that if the field is not required, an **empty value** will always pass the validation.
{% endhint %}
## How to add a conditional rule
You can add a conditional rule to a form field to control the **dynamic behaviour of the field**. For instance you may want a field to be shown only when another field assumes a certain value.
In order to set a conditional rule, the booking form must contain at least one field which is capable of driving conditional behaviour. Those fields are:
* Options (dropdown)
* Checkbox
* Number
So any other field may depend on their values. Inside the **`Conditional`** section of the form field you can set the status of the field (*Visible*, *Hidden*, *Required*, *Not required*), the control field (one of the above) and the value which triggers the status.
Adding a conditional rule to a field
## How to hide a field from registered users
To hide a form field from a registered user (read: to made it available only to guest users) just turn on the setting inside the **`Advanced`** section of the form field settings panel.
Hiding a field from registered users.
## How to deactivate a form field
There are certain situations in which you may want to deactivate one or more form fields, for example in case you don't need the built-in phone field, or in case you need to temporary turn off a field.
The active state of a form field is controlled by the switch in the form field header.
{% hint style="info" %}
The **Email** field can't be deactivated.
{% endhint %}
