The screen shot you shared is for webMethods Integration Server to perform activity as an SFTP client to a remote SFTP server. You enter the location of your private key here. [Edit] This location is on your wM IS file system. Not on the SFTP server. [/Edit] Never share this with any client. And a client will never share their private key with you. You do not need it.
YOU are the client in this screen, not the SFTP server you’re connecting to. This configuration screen is for you, as a client, to connect to someone’s SFTP server.
On that SFTP server, they will place your public SSH key on it, associated with your account. The SSH handshake performed when you connect to their server will use the public and private key to confirm to the SFTP server that you are who you say you are.
HTH.
#webMethods#SFTP#Integration-Server-and-ESB