Simple Class for building a Bootstrap-compatible Contact Form for ProcessWire

ContactForm.php

<?php

class ContactForm 
{
    var $form;

    var $to = 'destination@email.com';
    var $toName = 'Destination Name';

    public function __construct() 
    {
        $this->templates = wire('templates');
        $this->input = wire('input');
        $this->sanitizer = wire('sanitizer');
        $this->pages = wire('pages');
        $this->modules = wire('modules');
    }

    /**
     * Build the Contact Form
     */
    public function buildForm() 
    {
        $form = $this->modules->get("InputfieldForm");
        
        // Set the Form markup matching Bootstrap framework
        // We don't use labels, we just relies on the placeholder
        $form->setMarkup([
            'list' => "{out}",
            'item' => "\n\t<div class='form-group' {attrs}>\n{out}\n\t</div>",
            'item_label' => "",
        ]);

        $form->method = "POST";
        $form->action = "./";
        $form->class = "form";

        // Name field
        $singleField = $this->modules->get('InputfieldText');
        $singleField->attr('id+name', 'name');
        $singleField->attr('class','form-control');
        $singleField->placeholder = __("Name");
        $singleField->required = true;

        $form->add($singleField);

        // Email field
        $singleField = $this->modules->get("InputfieldEmail");
        $singleField->attr('id+name','email');
        $singleField->attr('class','form-control');
        $singleField->placeholder = "Email";
        $singleField->required = true;

        $form->add($singleField);
        
        // HONEYPOT email field
        $honeyField = $this->modules->get("InputfieldEmail");
        $honeyField->label = "Anti-Spam field! Dear screenreader user. Please leave this field out since it serves as spam detection.";
        $honeyField->attr('placeholder', 'Leave this field empty! Spam-protection!');
        $honeyField->attr('id+name','hp_email');
        $honeyField->required = 0;

        $form->add($honeyField);

        // Subject
        $singleField = $this->modules->get('InputfieldText');
        $singleField->attr('id+name', 'subject');
        $singleField->attr('class','form-control');
        $singleField->placeholder = __("Subject");
        $singleField->required = true;

        $form->add($singleField);

        // Message
        $singleField = $this->modules->get('InputfieldTextarea');
        $singleField->attr('id+name', 'message');
        $singleField->attr('class','form-control');
        $singleField->placeholder = __("Message");
        $singleField->required = true;

        $form->add($singleField);

        // Submit button
        $submit = $this->modules->get("InputfieldSubmit");
        $submit->name = "submit";
        $submit->value = __("Send");
        $submit->attr('class','btn btn-info');

        $form->add($submit);

        return $form;
    }

    /**
     * Send the email
     */
    public function sendMail($input) 
    {
        $wireMail = new WireMail();
        $wireMail->to($this->to);
        $wireMail->from($input['email']);
        $wireMail->toName($this->toName);
        $wireMail->fromName($input['name']);
        $wireMail->subject($input['subject']);
        $wireMail->body($input['message']);
        $numSent = $wireMail->send();

        if ($numSent > 0) {
            return true;
        } else {
            return false;
        }
    }
}

Thank you for that. Could you explain how do I link this code to my form? Sorry for the simple question.

@marcioellobo check out this thread https://processwire.com/talk/topic/2089-create-simple-forms-using-api/ it will provide all the answers that you need.

Thank you, so much!