How to add multiple documents in Sanity schema structure?

Looking at your question, I believe you're asking about how to reference multiple documents in a schema field. The most common way to do this in Sanity is using an array of references.

Here's how you structure it in your schema:

{
  name: 'relatedArticles',
  title: 'Related Articles',
  type: 'array',
  of: [
    {
      type: 'reference',
      to: [{type: 'article'}]
    }
  ]
}

This allows editors to add multiple document references to a single field. If you want to reference multiple different document types in the same array, you can do:

{
  name: 'resources',
  title: 'Resources',
  type: 'array',
  of: [
    {
      type: 'reference',
      to: [
        {type: 'article'},
        {type: 'video'},
        {type: 'podcast'}
      ]
    }
  ]
}

As explained in the array fields documentation, array fields create orderable collections where editors can:

• Add as many items as needed
• Reorder them via drag-and-drop
• Remove items
• Each item gets a unique _key automatically

You can also mix different types within the same array if you need more complex structures:

{
  name: 'content',
  title: 'Content Blocks',
  type: 'array',
  of: [
    {
      type: 'reference',
      to: [{type: 'article'}]
    },
    {
      type: 'image'
    },
    {
      type: 'object',
      name: 'textBlock',
      fields: [
        {name: 'text', type: 'text'}
      ]
    }
  ]
}

The array approach is much more flexible than single reference fields and is the standard Sanity pattern for "one-to-many" relationships. Editors can add unlimited documents (though you can add validation rules to set min/max limits if needed).