A developer can, if s/he so chooses, write a TOS document, an EULA, and/or a privacy policy. There is a risk that such a self-written document may not have the desired legal effect, if a legal challenge occurs, or the documents are significant in some legal case. If the documents are similar to those used by several other similar apps published by large firms, this risk may be reduced.
There is no central authority that must approve such documents.
The wording of such documents is, in theory, subject to copyright protection. Copying a legal document without permission could be copyright infringement, and the copyright holder could sue. However, many legal documents are slightly modified versions of standard or commonly used documents, which in turn are modified copies of earlier somewhat similar documents. There may not be enough original content in a TOS very similar to everyone else's TOS for it to be protected by copyright. Even if it is protected, it is unlikely to be registered, so (in the US) statutory damages will not be available, and only actual damages, based on the value of the TOS document as a document could be obtained in a copyright suit. That would not be a large sum, and the copyright holder might well not choose to sue over such a sum. Theere would still be some risk, of course.
If the developer takes the ideas from several existing TOS (or similar) documents, and uses them to create a different document expressing the same ideas, there is probably not a copyright violation. Copyright does not protect ideas, only expressions of ideas.