How to remove special characters from the SharePoint list column using calculated column - SharePoint online

Get Email User Name, email from SharePoint person field in list 

you can get user name and email from person field is the group or person coloumn 

Create PersonGroupCol  - person or group field

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 (Email, Name)
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]"
}
For User Name 
{
   "$schema": "https://developer.microsoft.com/json-schemas/sp/v2/column-formatting.schema.json",
   "elmType": "div",
   "txtContent": "[$PersonGroupCol.title]"
}

 Reference https://sharepoint.stackexchange.com/questions/278295/get-email-from-user-and-enter-into-sharepoint-list-field

other available fields are (not tested)

id
picture
jobTitle
department