“It got good reviews,” Ms. Cook said of the app.

The app presents one question per screen, which makes the form less intimidating, said Mark Kantrowitz, a financial-aid expert.

“It was actually fun to complete,” Mr. Kantrowitz said. “It makes completing the Fafsa much easier.”

The testers did flag some problems in the early version of the app. For instance, the college access network recommended that the app be more explicit in instructing both students and parents to sign the form.

Crucially, the app doesn’t yet allow automatic transfer of financial information from the Internal Revenue Service’s online Data Retrieval Tool, which makes it easier to accurately fill in financial details. Currently, users must use Fafsa.gov to take advantage of the I.R.S. tool. (While the website is now mobile-friendly, the I.R.S. tool itself isn’t “optimized” for mobile use, so that part of the process is still awkward, Ms. Cook said. Users must “scroll and zoom” to see all fields.)

The updated app, which will be released next month, will offer the I.R.S. tool with “full functionality,” according to an Education Department spokesman.

Here are some questions and answers about the Fafsa:

When can I use the new mobile Fafsa app?

The revised app is scheduled to become available Oct. 1, when the new Fafsa for the 2019-20 school year is released. The myStudentAid app can be downloaded from Apple’s App Store or from Google Play for Android devices.

The test app is available now for anyone who still wants to submit a Fafsa for the current academic year. But because the app doesn’t support the I.R.S. data tool, Diane Cheng, research director at the Institute for College Access and Success, advises students and their parents to avoid using it for 2018-19. Rather, she recommends using the website, https://fafsa.ed.gov, which allows automatic transfer of financial information with the I.R.S. tool, reducing the chance of errors that may delay processing of the form.