Display email from a person column

JamesPhImp 

Solution 1:

You can create a power automate flow on item creation/item update to update the Email address field based on the Person or Group field.

Solution 2: Customize list forms using Power apps and set default value of email address field based on the Person or Group field.

Solution 3: If you are not going to use those email address values later (you don't need to save emails in column) and you just want to show the email in SharePoint list view then you can also achieve it using JSON column formatting.

1. Create one single line of text column.
2. Hide it from list forms (make it Hidden from content type settings).
3. Then use below JSON code to format the column: 

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

Where PersonGroupCol is internal name of person or group field.

Output: 

Similar thread: Get Email from user and enter into SharePoint list field 

Related read: How to find the Internal name of columns in SharePoint Online? 

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