If you require that all applicants express interest through your online application system, there is no particular reason to continue using job applications, job interest forms, or other methods used to express interest or collect information from candidates. Some companies use employment applications or job interest forms after candidates express interest using an online application system (OAS) in order to get signatures expressing consent for drug tests, background checks, and so on, or to get signatures from candidates attesting that everything provided to the company is true and accurate. However, from what I know, there is no reason this could not be done via the OAS using an e-signature. (I want to state that I am not an attorney, and there may be some specific legal requirement connected to your company that would necessitate getting a regular signature rather than an e-signature. This would be a reason to have a candidate fill out a subsequent application form or job interest form.) Some companies use a job interest form for employees to express interest in positions that will be filled internally. Again, there is no regulatory requirement to do this. Internal candidates, like external candidates, can be required to express interest through an OAS.
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.