try this it should work for you

XML side

<button name="create_invoice" type="object" string="Create Invoice" />

Python side

def create_invoice(self):

	# your other code before open view
        
        return {
            'name': 'invoice', # Lable
            'type': 'ir.actions.act_window',
            'view_type': 'form',
            'view_mode': 'form',
            'res_model': 'account.invoice', # your model
            'target': 'new', # if you want popup
            'context': ctx, # if you need
        }