NEW YORK (Reuters) - JPMorgan Chase & Co (>> JPMorgan Chase & Co.) is gradually introducing a digital mortgage platform where customers can apply online and track applications by mobile phone.

The tools will allow customers to submit and sign documents online and exchange messages with bank staff and real-estate agents so loans can close more quickly and easily, consumer mortgage chief Mike Weinbach said in an interview.

"This platform will allow us to be where more of our customers are, which is online and on their phones," Weinbach said. "It is more efficient for customers and for us."

Applying for a mortgage can make or break a bank's relationship with a customer because home purchases are often the most expensive, complex and emotional transactions people make in their lifetimes.

JPMorgan started pilot-testing its digital tools in recent weeks and will make them available to more people before completing the rollout in 2018.

Offering the process online has become an imperative as customers have lost patience with the tedious and paperwork-heavy ordeal. Some 150,000 home loans JPMorgan made last year came through its branches and telephone lines, which will continue to be available for applications.

"Five years in the future, every lender is going to have a digital offering for their customers, or they're probably not going to be in business," Weinbach said.

Detroit-based Quicken Loans Inc first brought digital home loans into the mainstream about a year ago with a major advertising campaign for its Rocket Mortgage product.

Bank of America Corp (>> Bank of America Corp) introduced a Home Loan Navigator tool in June to handle applications online.

"It is more important for us to get it right for our customers," said Weinbach. "It is less important for us to be first."

The bank is using technology from Roostify, which sells software to the mortgage industry. Founders of the San Francisco-based company have said they started it after their own frustrations with buying homes.

JPMorgan is the No. 2 U.S. mortgage lender, behind Wells Fargo & Co (>> Wells Fargo & Co), according to Inside Mortgage Finance data for the first nine months of 2016. In the past few years, Quicken climbed to No. 3, in part because of the ease with which its customers can process applications. Bank of America ranked fourth. [L1N196059]

(Reporting by David Henry in New York; Editing by Lauren Tara LaCapra and Lisa Von Ahn)

By David Henry