If you have an employee that you want and expect to move to the open position, there is no federal regulatory requirement to post the job so that other candidates can express interest. You would track this action by showing it as some sort of job change (whether promotion, transfer, reclassification, or something else) in whatever system you use to record information on personnel activity. A more interesting question is whether you are required to collect and record information on any other internal candidates who have expressed interest in this job. If there are other internal candidates, I'd encourage you to keep track of who these candidates were and why there were not selected. These other internal candidates would probably be considered "applicants" under OFCCP's revised regulations regarding veterans and individuals with disabilities, and should be included in the data metrics associated with your AAPs for veterans and individuals with disabilities. (Conversely, it is not clear that these internal candidates would be considered "applicants" under OFCCP's Internet applicant rule or other regulatory guidance associated with Executive Order 11246.)
You can use this OFCCP audit checklist to ensure you're doing what is required to maintain OFCCP's regulations including VEVRAA, Section 503, and EO 11246. Or request a demo to streamline your compliance and recruiting efforts.