Setup: Blueprints

Add a Field named autoid with type hidden to your Page or File blueprints. Also set translate: false unless you need different autoids for different languages. More examples can be found here. You can also set values for a custom label and help property.

 content:
  type: fields
  fields:
    text:
      type: textarea
    autoid:             # <-------
      type: hidden
      translate: false
      # label: Automatic ID
      # help: Use this to link related pages savely      

This Plugin has an optional Field called autoid which is a non-translatable and disabled Text-Field. Use it with type: autoid.

 content:
  type: fields
  fields:
    text:
      type: textarea
    autoid:             # <-------
      type: autoid  

Structures

To keep the AutoID value unique you must make the structure non-translatable.

 content:
  type: fields
  fields:
    mystructure:
      type: structure
      translate: false      # <-------     
      fields:
        text:
          type: textarea
        autoid:             # <-------
          type: hidden
          translate: false