PackageMaker is mostly a GUI for the Julia package PkgTemplates
Depending on your choice, a different set of options will be selected, which you however can override manually.
Project.toml
you can of course always add packages later on by using Pkg
Pkg
.jl
Most of the functionalities of PkgTemplates is provided by plugins. The following section provides access to those plugins which are included in the default installation of PkgTemplates
PkgTemplates