Hello, 

You can add integer filed with name of id like below:

id = fields.Integer(string="ID")

I hope it's working.

Thanks

Hello Luis,

You would first need to create a new ID field as Manish said but for what you want to achieve there is a bit more to this. 

You would also need to create a sequence which can be seen here. The fields are pretty obvious to understand, in your case you would want a sequence size if 0 as for no padding, step of 1 and the next number would be 1 (starting number for now). Keep note of the "Sequence Code", this will be used later. This can be found in Settings->Technical->Sequences, here is my example. 

You would then need to create an automated action which will get this new number and assign it to the new field that you have created. For this, you would need to go to Settings->Technical->Automated Actions. Create a new one with the relevant fields: Model->Lead/Opportunity, Action To Do->Update the record, Trigger->On creation. Then in the One2Many select your new field set it as a Python Expression and write the value:

record.env["ir.sequence"].next_by_code("")

Now when creating a record you should be good to go. 

Hope this helps, 

Thanks, 

Hi,

If you need to set the sequence for the lead without any custom modules, ie from the user interface itself, you can add a new field using the developer mode and also assign a sequential value using the Automated action in Odoo.

To add a field to hold the sequence in the lead, we can do like this:  How to Add Custom Field From User Interface In Odoo

Once the field is added to the view, we need to set the auto incremental sequential value, for that you can create a automated action, for that Settings -> Technical -> Automation -> Automated Action.

See: Assign Sequential Value For Field Using Automated Action And Sequence

If yo don't want to do from ui itself, you can do it from the custom module, for that see how sequential value can be set from code in odoo: How to Add New Sequence in odoo12

Thanks