You could watch this video about multi branch: https://www.youtube.com/watch?v=gXXwCki94ys
Basically it is about:
create new item
copy and paste the git url of the project
choose a ssh key that has been added to the credentials settings
choose a polling interval of e.g. 1 min in the "scan multibranch pipeline triggers" section
It might have a chance for me to misread your question at the first time, so let me add another one.
If you meant by Jenkinsfile as you have a manual parameter input in Jenkinsfile for Multibranch or Github Org pipeline, then probably bad idea.
Those kind of jobs should run with predefined parameters or take them on-the-fly like manipulating some ...