Interesting. I was just messing around with my iPhone when I noticed that Vanguard updated their app with “Mobile Check Investment.” In other words, you can now snap a picture of a check and invest it in an eligible account.
This is similar to the remote deposit functionality introduced by a number of banks. The checks in question can either be checks that others have written to you or a check that you have written and made payable to Vanguard.
This service is available on both iOS and Android devices. Deposits can be made into individual accounts, traditional, Roth, and rollover IRAs, and joint, custodial, or trust accounts.
If they receive your check(s) by 4pm on a business day, your trade date will be that same day. If they’re received after the close of business or on a non-business day then your trade date will be the next business day. Funds will be available for withdrawal after seven days.
You can see here for additional details.