This is a fairly common "newbie" request. The short answer is "No" you cannot dynamically add fields like this.
But the long answer is : "you don't have to do that to get what you describe".
What you do is add more related records as needed instead of adding more fields.
To use your email example, You can define a related table for email addresses that you link to your contacts table. Using a portal to emails from the contacts table, you can then add as many email addresses as you need. When I set up a Contact Manager feature in a database, I typically set up one related table where I list all email addresses, phone numbers and social media URL's in one table. I use one field for the number or URL and a "label" field to identify it.
Ah, that makes sense. Thanks for the quick response, and sorry for the repeat question!
No apologies needed! This is a forum primarily for "newbies" and if you hadn't asked the question, you would not have gotten the answer that you need.