can i secure sql server agent job with password I want to secure SQL Server Agent jobs with password or any other method is it possible?
One alternative method which might help you out is to save your stored procedures and UDFs that the job may use (if any) WITH ENCRYPTION.

However, given the nature of your question, I wonder whether you really need to start a bottom-up review of your database systems security first, liaising with business owners regarding what permissions currently exist, and what the desired position should look like.