Hi,

Try this method:

1.Create a new Python file or use an existing one and define a new model that inherits from sale.order.from odoo import models, fields, api

class SaleOrder(models.Model):
    _inherit = 'sale.order'

    qty_invoiced = fields.Float(string='Invoiced Quantity', compute='_compute_qty_invoiced', store=True)

    @api.depends('order_line.qty_invoiced')
    def _compute_qty_invoiced(self):
        for order in self:
            order.qty_invoiced = sum(order.order_line.mapped('qty_invoiced'))
2. In the XML file (your_module/views/sale_order_views.xml), extend the Sale Order tree view and add the new field.

<record id="view_order_tree" model="ir.ui.view">
<field name="name">sale.order.view.tree.inherit</field>
<field name="model">sale.order</field>
    <field name="inherit_id" ref="    sale.view_order_tree"/>
    <field name="arch" type="xml">
<xpath expr="//field[@name='invoice_status']" position="after">
                    <field name="qty_invoiced"/>
                </xpath>
            </field>
</record>

3. Update your manifest file to include the new XML file. Upgrade your module for the changes to take effect.