How do I make a field required?

​How to select if a field is required:
Click on New menu in the top of the page > People. Go to the Additional tab and scroll down and find the custom field. Select the down arrow next to the bold text ("Test").

Then, select Edit field.

The Editing Custom Field pop up will appear.
Under Options > toggle the button next to Is Required.

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Please Note: There's not a way to make a field required for some people and not required for others. A field can only be required or not required and that requirement applies globally.

Link to other articles:

How do I create a form with an electronic signature?

Limiting Access to People Custom Fields