I don't have the Heltec V3, but the model I was able to find online does support WiFi.

You need to connect to it using some other device. It can be with Bluetooth using an app, or via USB using a web client. Once you are connected to it, you can go to Radio Configuration and add the WiFi info in the Network settings.

Then, you need to figure out what its IP is. There are a few different ways to do it. Usually I log into my router and check the IP of the latest device to log into the WiFi.

You can then go to that IP via your browser, and you will see this:

You can then connect to it and interact with the device over the browser.

To interact with it using the python library, you set the device's IP as the NODE's interface. Here is an example of a very simple script that will connect to the node via its IP and cause it to automatically respond with 'Pong' to any message that it receives that contain 'Ping'.

import meshtastic
import meshtastic.tcp_interface
from pubsub import pub
import time

# Your Meshtastic node's IP
MESHTASTIC_NODE_IP = "192.168.8.149"

def onReceive(packet, interface):
    if 'decoded' in packet and 'payload' in packet['decoded']:
        try:
            message = packet['decoded']['payload'].decode('utf-8')
            sender = packet['from']
            if "Ping" in message:
                interface.sendText("Pong", destinationId=sender)
        except Exception as e:
            pass

interface = meshtastic.tcp_interface.TCPInterface(hostname=MESHTASTIC_NODE_IP)
pub.subscribe(onReceive, "meshtastic.receive")

while True:
    time.sleep(5)  # Keep the script running

In the radio settings you can setup the wifi network that you want to use.