You can deploy RPM modules to the repodata folder using the modules.yaml file which contains all the desired modules and then proceed to trigger a repository index to update the repomd.xml and other metadata files with the modules information.
You can perform the upload directly in the JFrog Platform UI or using the following command.
curl -u <USERNAME>:<PASSWORD> -XPUT "http://localhost:8081/artifactory/rpm-local/<PATH_TO_REPODATA_FOLDER>/modules.yaml -T <TARGET_MODULES_FILE_PATH>"
Trigger the reindex by running the Calculate YUM Repository Metadata API.