Where can I submit a chain of custody for proof of ownership of an address???
It's your signed message with an address you want to prove your ownership, but to sign it, you actually have to own private key of that public address.
What do you mean? Are you referring to staking an address on the forum as proof of ownership for your account and address here?
Check this thread here:
Stake your Bitcoin address hereDon't forget to add a signed message so that someone could verify you own that address.
Here is the guide on signing a Bitcoin message, and that thread can help OP learning how to sign a message, before staking his address.
How to sign a message?!A copy of it with visual images.
How to sign a message?!