cspell.json

{
  // Enable your dictionary by adding it to the list of `dictionaries`
  "dictionaries": [
    "custom-words"
  ],
  // Tell CSpell about your dictionary
  "dictionaryDefinitions": [
    {
      // The name of the dictionary is used to look it up.
      "name": "custom-words",
      // Path to the custom word file. Relative to this `cspell.json` file.
      "path": "./.cspell/custom-words.txt",
      // Some editor extensions will use `addWords` for adding words to your
      // personal dictionary.
      "addWords": true
    }
  ]
}