initialValue not working for string field in existing Sanity document

Your schema looks correct, but there's an important detail about how initialValue works in Sanity: it only applies when creating new documents, not to existing ones.

Both of your approaches are valid syntax:

// Field-level initialValue
fields: [
  {
    name: 'title',
    title: 'Title',
    type: 'string',
    initialValue: 'Hello World',
  },
]

// Document-level initialValue
initialValue: {
  title: 'Hello World',
}

However, if you're testing this on a document that already exists (even if the title field is empty), the initialValue won't populate. This is by design - as explained in the Initial Value Templates documentation, initialValue only sets values when you first create a brand new document.

To test if it's working:

1. Go to your Studio
2. Create a completely new "Information" document (not editing an existing one)
3. You should see "Hello World" pre-populated in the title field

If you need to set values on existing documents:

You'll need to use a migration script with the @sanity/client. Here's an example:

import {createClient} from '@sanity/client'

const client = createClient({
  projectId: 'your-project-id',
  dataset: 'your-dataset',
  token: 'your-token-with-write-access',
  apiVersion: '2024-01-01',
})

client
  .patch({query: '*[_type == "info" && !defined(title)]'})
  .set({title: 'Hello World'})
  .commit()
  .then(() => console.log('Done!'))

This would update all existing "info" documents that don't have a title yet.

The key takeaway: initialValue is for new document creation only, not for backfilling existing documents. If your field is showing up empty on existing documents, that's expected behavior!