Right now Swan does not have a custodial IRA product. We are working on launching one soon, but it is not yet operational.
In the meantime, the only way to purchase Bitcoin through Swan into your IRA or 401k is to set up a self-directed IRA or 401k, and then set up an independent LLC that your IRA or 401k purchases. To do that complex legal/accounting work you will need to contact your lawyer and financial advisor. Standard 401ks, ROTHs, or IRAs will not work. Then, once you have a self-directed retirement account set up we can gladly help you buy Bitcoin into it through Swan.
If you already have a self-directed LLC with an independent LLC please reach out to Support@swanbitcoin.com for instructions on how to set up the Bitcoin purchasing plan.