Yes. One conversion an hour is free, with no account needed, for a file within the free size limit. A paid plan removes the hourly limit and the size limit, and lets you add several files to one job.
Free conversions have a size limit per file, set by the type of file, and the page tells you when a file is over it. A paid plan removes that limit, so much larger files can be converted.
Several files in one job need a paid plan. Free use is one file per conversion, one conversion an hour. On a paid plan you can add several files to one job, then download each result on its own or all of them in one ZIP.
