Hello Mohamed Lamine Lalmi,

For that, you need to define footer in your wizard form view.

For example:-

<record id="unique_id" model="ir.ui.view">
    <field name="name">wizard.model.form.view</field>
    <field name="model">wizard.model</field>
    <field name="arch" type="xml">
        <form string="Wizard">
            <group>
                <group>
                    <field name="wizard_field_1"/>
                </group>
                <group>
                    <field name="wizard_field_1"/>
                </group>
            </group>
            <footer>
                <button name="method_name_for_pdf" string="PDF" type="object" class="oe_highlight"/>
                or
                <button name="method_name_for_excel" string="Excel" type="object" class="oe_highlight"/>
                or
                <button string="Cancel" class="oe_link" special="cancel"/>
            </footer>
        </form>
    </field>
</record>

Hope it will helps you.

Thanks,