Every "Required" field you add to your lead capture form adds friction. If a user feels that a quiz is asking for too much sensitive information (like a mandatory phone number), they are likely to drop off right before seeing their results.
To maintain a high conversion rate, add maximum of 2-3 required fields. Typically, these should be:
Name
Email Address
Toggle ON (Required): Use this only for the data points you absolutely need to identify the lead or send them their results.
Toggle OFF (Optional): Use this for secondary information like Phone Numbers or Company Names.
By marking a field as optional, you won't scare away "top-of-funnel" leads. However, your highly motivated leads—those most likely to buy from you—will often provide that extra information anyway. This allows you to prioritize your follow-ups without sacrificing total lead volume.