When I start a new ad campaign I typically will set up conversion tracking on the website and I'll track any possible way a website visitor can become a customer; sales conversions, calls, email link clicks, contact form submission, chat, etc.
It's important to identify which are macro and micro conversions for your campaign, however. For e-commerce campaigns for example, sales conversions are the macro and calls, email link clicks, contact form submissions and chats would all be micro-conversions.
Or as Google Ads calls it Primary and Secondary Conversions. The sales conversion would be your Primary and the others would be Secondary, meaning they won't show up 'in-column' on the campaign and won't be included in campaign optimization.
This is good because you don't really want to optimize the campaign to increase calls, only sales conversions. But you'll still be able to report on how many Secondary Conversions came from the campaign, which is great for getting the full picture on how your Google Ad visitors are responding on your website.