Capital gains are taxed according to tax regulations of the country of your tax residency. We recommend that you consult a tax advisor for tax-related questions.
All dividends of US-listed securities are subject to 30% dividend withholding tax (subject to QII rule). These taxes are applicable as long as you own US listed assets, regardless of whether the assets were bought through StashAway, or via your own broker. The WHT is held at source and the rest of the dividends are redistributed back to your portfolio(s) and reinvested automatically.