Hello, there are a lot of bounties which will not accept Newbie's membership in joining their signature campaigns, But you can participate in campaigns such as Twitter, Facebook, YouTube and blogs, You must publish useful posts in order to get Merit in order to upgrade your account rank, Yes, all the bounties here accept the members of the bitcointalk forum to join, I advise you to read the rules of any campaign before participating, Any question related to the bounty, I advise you to ask the manager of the bounty before you do any work, so that you get your full stakes.