Hi,

If you are using odoo enterprise and subscription includes odoo studio, better to do the customization using the odoo studio, which will make your future upgrading to higher version easier for you.

Studio is a built in tool/app, that comes along with the odoo enterprise which end user can use for customizing the system as per the need. Studio can be used by anyone, as adding a field is just a drag and drop.

To know more about how to use odoo studio, see this:  

The things that we achieve using studio can also done via code, if you have technical knowledge in odoo, if you need to know how modules are built in odoo using the code, see this tutorial of the same: https://www.youtube.com/watch?v=I8FNdellz3Y&list=PLqRRLx0cl0homY1elJbSoWfeQbRKJ-oPO&index=2

Thanks