CYA
Simplify Tail Risk Strategy ETF
stock NYSE

Real answer: it doesn't really matter what "computer" you use for this. If you want a digital option for storage then all you really need is an external hard drive. If you search Amazon for "external hard drive" then you'll get a number of options that will do what you're looking for. Honestly, you could pick one blindfolded and it would probably work without a hitch. You can plug it into the USB port if whatever computer you use at the office and transfers the files as needed. 
That said, it's a very bad idea to rely on this for document retention, particularly as legal CYA. Hard drives can fail at random times for all kinds of reasons. They're *usually* fine but the risk of failure weighed against the consequences in a worst case scenario means that you need to have some kind of backup. For that, you'll either want to spend money for some kind of online backup solution (you could technically use a free Google Drive for this but God help you if you ever forget the password or need any kind of support) or go for the tried and true analog method of printing everything out and keeping it in bankers boxes. 

Mostly boilerplate, but not imaginary. The basic point is your fund assets should be segregated, so manager failure is not meant to wipe out investors, but operational failure, fraud or a messy insolvency at the depositary chain can still create some loss or delay risk at the edges. So I would read that wording as legal CYA around low-probability plumbing risk, not as a sign that plain vanilla ETFs are suddenly unsafe.

One bit of received wisdom is that there is no need to worry about any counterparty (custodian, manager, depositary) default risk causing losses in my ETF holding. However, I am looking at a KID (for MVOL in this case) which uses the following language:
"What happens if BlackRock Asset Management Ireland Limited is unable to pay out?
The assets of the Fund are held in safekeeping by its depositary, State Street Custodial Services (Ireland) Limited (the “Depositary”). In the event of the insolvency of the Manager, the Fund’s assets in the safekeeping of the Depositary will not be affected. However, in the event of the Depositary’s insolvency, or someone acting on its behalf, the Fund may suffer a financial loss. However, this risk is mitigated to a certain extent by the fact the Depositary is required by law and regulation to segregate its own assets from the assets of the Fund. "

The depositary part seems a bit weaselly, especially "to a certain extent". Is that just boilerplate legal CYA or is there a real risk that something may go wrong and funds may in practice not have been fully segregated after all? Leaving, of course, aside any considerations that a default of State Street would definitely mean something has gone wrong already...I notice that anyone "acting on (State Street Ireland)'s behalf" is included in this as well.