there is no existing field which can show me who all modified the record & filed tracking is disabled. Is there any other way I can pull the data who modified a particular record. Not looking for last modified but list of all modified users. any query which can help me to pull data? thank you
If you do not have History Tracking on the key fields enabled then you would not be able to do this in Salesforce.
You can track User logins by default using the login history and configuration changes using the setup audit trail, but with each record only changes on fields with history tracking enabled would be logged.