Form 5498 is used to report your total annual IRA contributions.
You will receive a 5498 if you owned a retirement account (such as your Aspiration IRA, or an external employer-sponsored plan account) and you either made a contribution (including catch-up contributions) to an IRA between January 1st, 2017 and April 17th, 2018 or you completed a rollover into an IRA during this timeframe.
While Aspiration sends a copy of this form to the IRS, it generally isn't necessary when you're preparing your tax returns. All you need to do is keep it for your records!
This form is distributed in May, because contributions can be made until April 17th, 2018 for the previous tax year.