GraphQL Error field type must be Input Type but got:

If you describe schema within schema.graphql file, just replace type to input:

Wrong:

type SomeData {
  someField: String!
}

Right:

input SomeData {
  someField: String!
}

Please change type CreateNotebookInput to input CreateNotebookInput

For those who are using graphql-tools and stumble accross this post, documentation is here at GraphQL's Website.

My Example using graphQL tools is here below: (this has an input inside of an input AKA an ImageInput inside the SocialPostInput)

//mutation file

extend type Mutation {
    SchedulePost ( 
        socialPost: SocialPostInput,
        schedule: ScheduleInput
     ): ScheduledPost
}`

//Schedule and SocialPost file

type Image {
    id: String
    url: String
}
type SocialPost {
    id: String
    GCID: String
    message: String
    image: Image
}
input ImageInput {
    url: String
}
input SocialPostInput {
    GCID: String
    message: String
    image: ImageInput
}
type Schedule {
    id: String
    month: Int
    date: Int
    hour: Int
    minute: Int
}
input ScheduleInput {
    id: String
    month: Int
    date: Int
    hour: Int
    minute: Int
}`

In GraphQL, an input cannot be used as a type and a type cannot be used as an input. Unfortunately, even if the fields appear identical to an existing type, you always have to define a separate input to use as an argument. Try something like this:

const NotebookDetailsInput = new GraphQLInputObjectType({
  name: 'NotebookDetailsInput',
  fields: () => ({
    id:          { type: GraphQLID },
    description: { type: GraphQLString },
    language:    { type: GraphQLString }, 
  })
});

If using SDL, the same type would look like this:

input {
  id: ID
  description: String
  language: String
}

Please see this answer for an extensive explanation of why it's necessary to do this.