Vivo V29 5G smartphone with a 12/256GB configuration, as product releases and specifications can change over time. However, I can provide you with a general description of what features you might expect in a high-end smartphone like this:

1. 5G Connectivity: The inclusion of 5G support allows for faster internet speeds and improved network performance.

2. Storage: With 256GB of internal storage, users have ample space to store apps, photos, videos, and other data.

3. Performance: A powerful processor, likely with multiple cores, ensures smooth performance for multitasking and demanding applications.

4. Camera System: High-quality cameras, both front and rear, with advanced imaging features for capturing detailed photos and videos.

5. Display: A large and vibrant display, possibly with high resolution and advanced display technologies for an immersive viewing experience.

6. Battery Life: A sizable battery to provide sufficient power for a full day of use, with possible fast-charging capabilities.

7. Operating System: The phone likely runs on the latest version of Android, customized with Vivo's user interface.

8. Design: A sleek and stylish design with premium materials, and possibly features such as an in-display fingerprint sensor.

9. Additional Features: Depending on the model and year of release, the phone may include additional features such as facial recognition, water resistance, stereo speakers, and more.

For the most accurate and up-to-date information, I recommend checking the official Vivo website or contacting Vivo customer support.