How do you add new product types?
Hello,
What kind of product types would you like to add ?
Because we recommend to not modify product types. If you do so it will modify some process in the application and you will have some problems.
The easiest way is to use product families and categories (Referential / Configuration to add some new) to define different type of products.
If you really want to change the selection in the product type field, you can potentially add types, but you should not remove existing ones and their order.
In case you want to add a new product type you should go in Administration / View Management / All selects. Then you should look for the select product.product.type.select (module axelor-base) and double click on it.
Click on edit, and in the panel items you can see the product types. To add one, click on +. The safe way is to add new ones after the existing title and to just fill the title field for the new ones.