Short answer: Clarivate states that only journal publishers are granted access to the Web of Science Publisher Portal and only journal publishers can submit new journal evaluation requests. Individual authors do not submit their papers to Clarivate for indexing.
Authors submit manuscripts to journals. If a researcher needs a Web of Science-covered journal, the author should verify current journal coverage in the Master Journal List and then follow the journal’s own submission process.
Publishers considering evaluation should use Clarivate’s official Publisher Portal and current journal selection criteria. A third-party service cannot submit an author’s paper directly into Web of Science as a substitute for journal publication.
This distinction is important when evaluating marketing claims from “indexing services.”
Official reference: Clarivate journal evaluation process.