Where to find the API KEY ???

Hi, I'm using DOCKER to install answer, I need the API KEY, The doc is here but not sure where to get the API key!

I need to make post requests to add users to my small comunity, as example:

data = {
  "display_name": "string",
  "email": "string",
  "password": "stringst"
}

  headers = {
    "Content-Type": "application/json",
    "Authorization": community_api
  }

Without API KEY, i always get 401 error:

{
  "code": 401,
  "reason": "base.unauthorized_error",
  "msg": "Unauthorized.",
  "data": null
}

Kindly someone reply with how I can get or define the API key for answer, Thank you.