There are 3 ways to deploy a new function via web job:
As I know, you could leverage WebJobs to execute custom jobs based on different types (scripts, executable programs, etc.) within the context of a web app. In order to minimize the impact of WebJobs on the performance of the web app, you could try to create an empty Azure Web App in the new App Service Plan to host your WebJobs which could do some long-running workflows, I/O-intensive jobs, CPU-intensive jobs, etc. I recommend that you could refer to best-practices-background-jobs. Also, there is a related thread about Azure Webjobs: One Job with several Functions, or several Jobs with 1 function each, you could refer to it.