Croatia, led by Marin Cilic, won the 2018 rendition against France under rules used since the inception of the tournament in 1900.
The old format featured several rounds of four singles and a doubles match over three days. The matches were the best of five sets.
From November 2019 at the Caja Magica in Madrid, 18 teams will gather over seven days to battle for the trophy.
Divided into six groups of three, they will play the pool stages over the first four days involving two singles matches as well as a doubles tie. The matches will be the best of three sets.
The six group winners and the two best runners-up will advance to the knockout stages.
Barcalona defender, Gerard Piqué, whose Kosmos company is pouring around 3 billion euros into a 25-year deal with the Davis Cup organisers, said: "We have been working for more than a year and we have created a great team to carry out this project."
Rafael Nadal, the world number two, is likely to lead the Spanish charge for a sixth title.
However world number one Novak Djokovic has said he plans to focus on the ATP World Team Cup which will be staged in Australia in January.
Djokovic's Serbian compatriots will feature in Group A with the 2018 runners-up France and Japan.
The 2016 victors Argentina, Germany and Chile are in Group C.
Group D will pit Belgium, Colombia and the 28-time champions Australia against each other.
Britain, who have been champions on 10 occasions, will be with Kazakhstan and Netherlands in Group E.
The United States, who have a record 32 victories are in Group F with Italy and Canada.