I am planning to use OJS to build a peer-review system for articles like ScholarOne or Editorial Manager.
Is there a limit to the number of journals that can be created?
Can additional journals be registered after the journal has been created? How can I register additional journals?
So far as we know, there is no limit to the number of journals you can create. If you’re just getting started with OJS, I’d highliy recommend the resources on our our documentation site: https://docs.pkp.sfu.ca
In particular, learning OJS 3, and the getting started section (both at the top), are really good introductions to OJS. If you’re going to be installing and running OJS 3 yourself, I’d recommend the administrator’s guide as well: https://docs.pkp.sfu.ca/admin-guide/en/