First of all, you have to install this module, and then your friends have to install this module.

Make this bag, and then stuff it in what you want to give friends

The moment you close the bag, you will find that your Minecraft folder has one more folder

Because it happened to be from M, it is usually near your Mods folder

Next, send the files in this folder to your friends,

Let your friends stuff this file into this folder

When he opens the bag, you can see the items you put in.

However, this file can be reused, and the things in your own bag will not disappear (╯‵ □ ′) ╯︵┻━┻