You have three main options:
1.) You can attached the charter/scope information as a document. This can be attached directly to the action plan or to subsets of the action plan.
2.) This can be pasted (or written) into the notes object, which again can be tied to the action plan or any subset. Notes support many pages of text.
3.) You can make custom fields for all of the data in the charter and populate the data in these fields (most cumbersome option, but allows you to easily report, sort, and filter by the data in the charter).