2. Click the "Trade" button
3. Switch the order type to Market
4. Tap the whole share button and switch it to fractional which would allow you to enter the quantity or amount that you would like.
5. Submit your order.
If you are submitting an order with a whole share attached, then the fractional order would need to be placed separately from the whole share order. For example, if your goal is to own 1.5 shares of ABC stock then you would need to buy one whole share and then place a separate order for the partial share of 0.5.