To connect your **HP Envy 6400e printer to Wi-Fi**, follow these steps:

1. **Put the printer in wireless setup mode**:
– Locate the wireless button at the back of the printer just below the power button.
– Press and hold this wireless button for about 3 seconds until the front light changes to purple. This indicates the printer is in wireless setup mode[1].

2. **Use the HP Smart app to connect the printer to your network**:
– On your smartphone or computer, download and open the **HP Smart app** (available for iPhone, Android, Windows, Mac).
– In the app, tap the plus (+) button to add a new printer.
– Select your **HP Envy 6400e series** printer from the list.
– Confirm your Wi-Fi network name when prompted and connect the printer.
– Once the printer connects, the purple light will stop blinking and remain steady, indicating a successful Wi-Fi connection[1][2][4].

3. **Complete setup for full functionality**:
– After connection, finish the setup steps in the HP Smart app.
– Press the flashing information button on the printer if prompted to accept printing services or HP offers.
– You can choose to join HP+ or skip that offer as per your preference[1].

4. **If you changed your Wi-Fi router or network**:
– You may need to reset the wireless settings on your printer before re-connecting.
– To do this, you can restore the wireless settings to factory defaults and repeat the setup steps above.
– HP provides detailed guides for resetting and reconnecting on their support pages[3][5].

These steps generally apply whether you use a smartphone or a computer and should help your HP Envy 6400e printer connect to your Wi-Fi network successfully[1][2][4].

If you encounter issues, ensure your device is on the same network you want the printer to connect to, and consider restarting your router and printer before retrying the setup. For further troubleshooting, HP Support Community forums and official HP support pages offer additional assistance[3][5].