United Airlines joined American Airlines as the second U.S.-based airline to introduce digital proof of a negative COVID-19 test while traveling.

United’s app and website have added a “Travel-Ready Center” section that’s a COVID-19 “passport.” Travelers can upload COVID-19 test results and necessary vaccination information.

There are step-by-step instructions on the app to make sure passengers know exactly what to do when they go to upload any documents.

"Starting today, our 'Travel-Ready Center' gives customers a personalized, step-by-step guide of what is needed for their trip, a simple way to upload required documents and quickly get their boarding pass, fully integrated within our app and website,” Linda Jojo, United's Executive Vice President for Technology and Chief Digital Officer, said in a press release.

This section also includes information about different country’s entry requirements and where testing facilities are located while traveling.

The Center for Disease Control and Prevention has just announced that travelers entering the U.S. must show proof of a negative COVID-19 test at least three days prior to travel, which will go into effect on Tuesday, Jan. 26.

United suggests that travelers still bring a hard copy of their negative test results.

American Airlines’ VeriFLY app works in a similar way to United’s including a spot to upload documents and entry information about where you might be traveling to and from.

United Airlines announced a contract tracing initiative on all flights in the effort to contain Covid-19
United Airlines announced a contract tracing initiative on all flights in the effort to contain Covid-19 GETTY IMAGES NORTH AMERICA / MARIO TAMA