I created an address with a local copy of MoneroAddress.org (based on a custom entropy string, which I stored securely) and I want to send some XMR there.
The sending client asks for the address and a payment ID. In earlier cases, whenever sending Monero the recipient specified their payment ID but now I have to create one myself.
Note: I don't need to receive more XMR (or be able to distinguish different sources) on this address than just this one transaction.
Can I just specify any random payment ID there? Payment IDs seems to be 256 bit hex strings, can I just take the sha256 of some random gibberish input and use that?
Do I need to save the payment ID in order to spend my funds later?