Vivo X90 5G with 8GB RAM and 256GB storage, as product details may have been released or updated after that time. However, I can provide a general overview of features commonly found in smartphones:

1. Display: The Vivo X90 5G is likely to feature a vibrant and high-resolution display for an immersive viewing experience.

2. Performance: With 8GB of RAM and 256GB of internal storage, the device should offer smooth multitasking and ample storage space for apps, media, and files.

3. Processor: The smartphone may be equipped with a capable processor, possibly from a reputable manufacturer, to ensure efficient performance and support for 5G connectivity.

4. 5G Connectivity: As indicated in the model name, the Vivo X90 5G is expected to support 5G connectivity, providing faster data speeds and improved network performance.

5. Camera System: It likely features a sophisticated camera setup, including multiple lenses for capturing high-quality photos and videos. Vivo often focuses on camera capabilities in their smartphones.

6. Battery Life: The device may come with a decent-sized battery to provide satisfactory battery life, complemented by optimization features to enhance power efficiency.

7. Operating System: It should run on the latest version of Android with Vivo's custom user interface on top, offering a user-friendly experience.

8. Design: Vivo phones usually feature sleek and modern designs, and the X90 5G is likely to follow suit.

9. Additional Features: Look out for additional features such as facial recognition, fingerprint sensor, fast charging, and possibly other unique features that Vivo tends to incorporate into their smartphones.