Working with jenkins credentials
You should specify which 3rd party service you will work on.Below is an example of credentials with bitbucket
I am now working with Jenkins ver. 1.568.By default, there's Credentials feature. So, if you want to add a credential, just click on Add Credentials. For example, I'd like to add SSH Username with password, so I can use it in checking out code from bitbucket
Credentials plugin - provides a centralized way to define credentials that can be used by your Jenkins instance, plugins and build jobs.
Credentials Binding plugin - allows you to configure your build jobs to inject credentials as environment variables.
The third party plugins need to be installed in your Jenkins instance. For example, Assembla Auth Plugin allows you to authenticate to an Assembla repository.
Which 3rd party services are you working with?
Instead of using SSH Username with private key you can simply use username with password option