Ability to add more exported fields in APM

I am using node.js agent. the apm and the entire ELK stack is updated too->
2018-10-08T11:10:03.569+0800 INFO instance/beat.go:225 Setup Beat: apm-server; Version: 6.3.0

the issue may be not related to the version of the apm.

maybe I am unable to articulate the problem clearly/correctly.

I am providing a screenshot from kibana to see if it can help.

image

as you can see, the fields are captured but not indexed.