For basic conversion tracking, use Google Analytics 4 events. The Google Analytics contrib module handles the tracking code, and you configure events in GA4 to mark key actions like form submissions as conversions.
For more advanced tracking, install Google Tag Manager for Drupal. This lets you manage tags and triggers through the Tag Manager interface without touching Drupal configuration. It is ideal for marketing teams that want to iterate quickly on tracking without developer involvement.
For form specific tracking, the Webform module has built in integration with various analytics platforms. You can also add custom JavaScript to fire events when specific forms are submitted or specific pages are viewed. Consider privacy regulations like GDPR when implementing tracking. Most conversion tracking involves personal data and needs user consent, which modules like EU Cookie Compliance can help manage.