Software Ideas Modeler offers tools for following elements of a package diagram:
The package element is a group of elements, which defines their namespace.
It merges a package to another package. Multiple packages may be merged to a single package. The Merge relation points to a merged package from a package whose content is being merged. The merged package contains all the content from all packages which point to it.
It allows to use elements from imported package with unqualified names in the target package. The relation arrow from an imported package points to a target package.
The Use relationship shows which package is publicly used by a package. It is used for depicting the usage of interfaces.
The Access relationship shows which package is accessed by a package. It expresses private usage.