Hello, 

There are two kind of solutions:

Solution 1: 

import xmlrpc.client

# Odoo XML-RPC parameters
url = 'http://your-odoo-instance'
db = 'database_name'
username = 'user'
password = 'password'

# Connect to Odoo XML-RPC server
common = xmlrpc.client.ServerProxy('{}/xmlrpc/2/common'.format(url))
uid = common.authenticate(db, username, password, {})

# Create a proxy object for the CRM module
models = xmlrpc.client.ServerProxy('{}/xmlrpc/2/object'.format(url))

# Create a lead in Odoo
lead_data = {
    'name': 'John Doe',
    'contact_name': 'John Doe',
    'email_from': 'john@example.com',
    'description': 'Interested in your products',
    # Add more fields as needed
}
lead_id = models.execute_kw(db, uid, password, 'crm.lead', 'create', [lead_data])

Solution 2: 

from odoo import http
from odoo.http import request

class ExternalFormController(http.Controller):
    
    @http.route('/your/endpoint', type='http', auth='public', methods=['POST'])
    def handle_contact_form(self, **post):
        # Extract data from the incoming request
        name = post.get('name')
        email = post.get('email')
        message = post.get('message')
        
        # Create a lead/contact in Odoo
        Lead = request.env['crm.lead']
        lead_vals = {
            'name': name,
            'contact_name': name,
            'email_from': email,
            'description': message,
            # Add more fields as needed
        }
        lead = Lead.create(lead_vals)
        
        # You may want to return a response to the external form indicating success or failure
        return "Success"  # Or you can return JSON/XML response