The measures include a simplified front wing with a larger span, front brake ducts without winglets and a wider and deeper rear wing.
The International Automobile Federation (FIA) said its Formula One commission, Strategy Group and World Motor Sport Council had approved the changes.
The changes should reduce turbulence for cars that are following each other, and come after criticism of the lack of overtaking in some races.
The FIA said the vote, on the last day before unanimous agreement is required for any 2019 regulation changes, followed research carried out by a majority of the teams and backed by commercial rights holders Liberty Media.
"These studies indicated the strong likelihood of a positive impact on racing and overtaking within F1 and as such have now been ratified for implementation in 2019," the statement added.
"The approved changes are separate to the ongoing work being undertaken in regard to defining Formula One's regulations for 2021 and beyond."
Motorsport.com suggested several teams, including Ferrari and Red Bull, had been opposed to the proposals but were outvoted.
Formula One's current agreements with teams expire at the end of 2020 and all parties are discussing what kind of engine and rules should be introduced after that.
Liberty want to level the playing field, reduce the costs and introduce a more equal distribution of the revenues.
Only three of the 10 teams — Mercedes, Ferrari and Red Bull — have won races in the V6 turbo hybrid era that started in 2014, and Mercedes has so far won every championship.
The FIA said it was continuing to evaluate a range of other measures to encourage closer racing.