Hi Jacquelyn Zalar,

 You have to first configure outgoing mail server of Odoo to send an email from Odoo.Then create a mail template in XML file.   e.g.

  <record id="email_template" model="mail.template">

         <field name="name">name of template</field>

         <field name="email_from">email address of sender</field>

         <field name="subject">subject of email</field>

         <field name="model_id" ref="base.model_ir_ui_view"/>

         <field name="body_html"><![CDATA[

       <p>

     Your mail-content

    </p>

         ]]></field>

     </record>

    Then write below python code in file where you have written code for leads

    template_id = request.env['ir.model.data'].get_object_reference(your module name,mail template id(email_template))

    template_obj = request.env['mail.template'].browse(template_id)

    template_obj.email_to = receiver's mail address

    template_obj.send_mail(page.id, force_send=True)

Hope this will helpful to you!

Thanks