The new functionality means customers can save Covid-19-related files, such as overseas country entry forms and negative test results, to their phones.
It also offers holidaymakers access to safe travel information and travel requirements for the destination they are travelling to and allows them to travel paper-free.
Package holiday customers can also view their holiday documents, including boarding passes, flights and transfer vouchers on the Jet2holidays app.
Flight-only customers are able to view and download their Jet2.com boarding passes and any other useful documents that they choose to upload.
Steve Heapy, chief executive of Jet2.com and Jet2holidays, said: "As a result of Government travel requirements, there are additional documents for holidaymakers to be aware of such as test results and passenger locator forms.
"As we start to welcome back more customers and increase our offering to include flights and holidays to over 40 quarantine-free destinations, we want to make the process of travelling with us as smooth as possible."