Click the "Copy ID" button next to the avatar’s name. This will save the avtr_ string directly to your clipboard. Why Do You Need an Avatar ID?
Avatar ID (often called a Blueprint ID ) depends on whether you are looking for your own creation or a public avatar you've found in-game. These IDs follow a standard how to get avatar id vrchat
If you need to update an existing avatar, you can find your uploaded avatars in the under the Content Manager tab and click Copy ID . On the VRChat Website : Navigate to the VRChat Home website. Click the "Copy ID" button next to the avatar’s name