By game design, all the items sent by our neighbors or friends are immediately delivered to the Inventory*. They only show up in the Envelope in the form of notifications so that:
- we get notified who among our friends or neighbors have answered our requests
- we know which items are given to us and which items to look for in the Inventory
- our friends get something in return (e.g. 5 Coins) after accepting their help
This means that the items sent by our friends automatically get stored in the Inventory* upon loading the game even if we do not "accept" them in the Envelope first.
For example, if you run out of Salt and "friend A" sends you one, the Salt count in the Inventory becomes 1/12 right after reloading the game. Then, if you access the Envelope to accept "friend A's" help, the Salt count won't increase to 2/12 since you have already received one upon entering the game.
*If the items given are building materials or quest-related, they are also automatically added to the respective buildings or quests/tasks.