Why am I asked to accept some permissions on installation?
The Shopify Platform has a permission system for Shopify apps. That way, the Shopify Platform controls which information from your store apps can access or modify.
Unfortunately, the permission system is coarse-grained and apps have to ask for a full chunk of information in order to get something particular. For example, if an app want to know the number of orders in your store, it has to ask for the read_orders permission, what also allows to read the detail of the orders or the order customer data.
The following are the permissions required by Shipping Rates Calculator Plus, as displayed by Shopify in the app installation page:
Let us explain in detail the meaning of each permission listed.
View Shopify account data
We need to know your Shopify plan, your contact email address and your store currency. This is a read-only permission, our app cannot modify any shop data.
Manage your Online store