It is difficult to determine a specific timeframe for how long it takes for a submitted proposal to become active on Upwork as it depends on various factors such as the client's response rate and whether or not they have logged in to view the proposals. Generally, a submitted proposal will show in the Submitted Proposals section until the client responds to it. If the client calls for an interview or contacts the freelancer, the proposal will then move to the Active Proposals page. It is also possible for a proposal to remain in the Submitted Proposals section if the client has not yet reviewed or responded to it. It is recommended for freelancers to forget about the proposal until they are contacted by the client and to let the client know if any changes need to be made to the proposed terms after starting the interview process.