There are two types of ARM licenses. One is an Architectectural license. This allows licensees to design and implement the ARM ISA. Apple and QCOM among others have Architectural licenses. They can add customizations such as # pipelines stages. This license is very expensive.

The other license is getting ARM's implementation of a CPU (ie A57, A72 etc). Customers can parametize # cores, cache size, memory width etc, but the basic architecture is fixed.