Unless your table includes a "InsertedBy" column that identifies the user when the INSERT operation is made, it's complicated, and will depend on the database system and the way it is used by you.
If it's a multiuser DB system like SQL Server or MySQL
and you use separate SQL user logins then you can use the Audit Log to access the info:
How to Enable SQL Server Audit and Review the Audit Log[
^]
But ... if your software doesn't do that, and / or it uses a single user DB, then you cannot find out who INSERTed or UPDATED a row.