add_file_wizard.xml

<?xml version="1.0" encoding="UTF-8"?>
<odoo>
    <!-- WIZARD FORM -->
    <record id="add_file_wizard_view_form" model="ir.ui.view">
        <field name="name">add.file.wizard.form</field>
        <field name="model">add.file.wizard</field>
        <field name="arch" type="xml">
            <form string="Ajouter un Fichier">
                <group name="infos" string="Informations">
                        <field name="partner_id" readonly="1" />
                        <field name="type" required="1" />
                        <field name="periode" required="1" />
                        <field name="validite" required="1" />
                </group>
                <group>
                    <field name="filename" invisible="1"/>
                    <field name="file" filename="filename" required="1"/>
                </group>
                <footer>
                    <button class="btn btn-sm btn-primary" name="add_file" string="Ajouter" type="object" confirm="Êtes-vous sûr(e) de vouloir ajouter ce fichier ?"/>
                    <button class="btn btn-sm btn-default" special="cancel" string="Fermer"/>
                </footer>
            </form>
        </field>
    </record>

    <record id="add_file_wizard_create_action" model="ir.actions.act_window">
        <field name="name">Ajouter un fichier</field>
        <field name="type">ir.actions.act_window</field>
        <field name="res_model">add.file.wizard</field>
        <field name="view_mode">form</field>
        <field name="view_id" ref="add_file_wizard_view_form"/>
        <field name="target">new</field>
    </record>

</odoo>