@Sunghan
In the append to an array variable, include this JSON code.
In Name put Display name of the attachment,
In $content-type and $content, Copy and paste the below code
{
"Name": "@{items('Apply_to_each')?['DisplayName']}",
"content": {
"$content-type": "@{body('Get_attachment_content')['$content-type']}",
"$content": "@{body('Get_attachment_content')['$content']}"
}
}