Hi,

In Odoo 16, we can add our new model to the Point of sale by inheriting the _pos_ui_models_to_load method in the “pos.session” model.

def _pos_ui_models_to_load(self):
    result = super()._pos_ui_models_to_load()
    new_model = 'your.new.model’
    result.append(new_model)
    return result

Now for adding the new field, we can use the _loader_params method, it is written as _loader_params_ followed by your model name

def _loader_params_your_new_model(self):
    return {
        'search_params': {
            'fields': ['new_field_1’, ‘new_field_2’'],
        },
    }

Regards