coc settings -> ~/.config/nvim/coc-settings.json

coc-settings.json

{
  "coc.preferences.formatOnSaveFiletypes": [
    "css",
    "markdown",
    "javascript",
    "javascriptreact",
    "graphql",
    "html",
    "yaml",
    "json",
    "python",
    "cpp",
    "txt"
  ],
  // python config
  "python.linting.enabled": true,
  "python.linting.pylintEnabled": true,
  "snippets.ultisnips.directories": ["UltiSnips", "~/.config/nvim/utils/snips"],
  // javascript config
  "javascript.format.enabled": true
}