Prints. The module's one printed document is the Donation Receipt, printed from the donation's page and self-filed like every print (§1.10): the donor's copy of the gift — its number, date, designation and amount. Your charity registration number belongs in the company's print footer (§0.8), so it rides on every receipt without being typed on any of them.
Links. A posted donation names the journal it created, and the journal names the donation back (Chapter 7). A designation leads to its gifts through the Donations list and the by-designation report; a donor, through Donations by Donor. The gift's own files — the transfer advice, the appeal letter it answered — attach to the donation record itself (§1.9), and Chapter 14 tells the whole documents story once.