All the app’s data (except for the stock prices) are kept in sync via your own iCloud account - automatically. This means that changes made on one device will within a minute or so appear on the other without you having to do anything.
Examples of things that sync automatically:
- Watchlists: add, rename or delete
- Stocks, Forex or Crypto Currencies: add, delete or move between watch lists
- Stock Parameters: changed display name
- Point and Figure Chart Parameters: e.g. box size and months of data to chart
- Line Chart Parameters: e.g. SMA or EMA, display precision
- Chart Colours: e.g. PnF chart Support Line colour, Line chart Top Fill colour
Note: the price data for a given stock is saved locally. However it is easily updated on all devices as needed.
Note 2: using iCloud is the default option but you can choose to store data locally rather than on iCloud.