Add indicators as any other module - general module loading documentation is also available on the main page of the Highcharts Angular wrapper GitHub repository.

After Highcharts is imported using Highcharts Stock (as a core like in the code snippet below, or as a Highcharts + stock module) use import and initialize the core indicator module first and all needed indicators next (e.g. ZigZag indicator) on the Highcharts variable.

import * as Highcharts from "highcharts/highstock";

const IndicatorsCore = require("highcharts/indicators/indicators");

const IndicatorZigZag = require("highcharts/indicators/zigzag");