Extract email from people picker in another column

RADical6142 Do you just want to show the email in list view or store the value in column & use it somewhere else?

If you just want "display" value in list view, you can use JSON formatting on column like: 

{
   "$schema": "https://developer.microsoft.com/json-schemas/sp/v2/column-formatting.schema.json",
   "elmType": "div",
   "txtContent": "[$PersonGroupCol.email]"
}

Output: 

If you want to store the value in column & use it somewhere else, you can create a power automate flow to update the Email address field based on the Person or Group field.

Check my answer given in this thread where I have explained same scenario in detail: Get Email from user and enter into SharePoint list field 

Please click Mark as Best Response & Like if my post helped you to solve your issue. This will help others to find the correct solution easily. It also closes the item. If the post was useful in other ways, please consider giving it Like.