Share registers before and after, the shareholders' agreement or term sheet, board and shareholder resolutions authorising the transaction, and a written explanation of the control chain.
Show both structures side by side and explain the difference
The most effective presentation is a pair of simple diagrams: the ownership chain as it stands and as it will stand, each supported by the underlying documents. Behind them place the certified share registers for both entities, the share purchase or subscription agreement, the shareholders' agreement in full, and the resolutions authorising the issue or transfer. Then add a short written explanation naming who holds voting control of the Canadian parent, who holds the shares of the American subsidiary, and which decisions require the new investor's consent.
Do not paraphrase the shareholders' agreement instead of providing it; a reviewer who suspects a document is being withheld will ask for it and will read the rest of the file more sceptically. If the transaction has not closed, say so plainly and give the expected date.