Workers voted by two to one to accept a deal agreed between the Communication Workers Union (CWU) and Royal Mail at the beginning of March.
Staff who are members of the Communication Workers Union (CWU) voted two to one in favour of a 6.9% pay rise over three years.
Roger Poole, independent chair of talks between Royal Mail and CWU, said: "I am delighted to see the positive ballot result of CWU members in favour of the Transformation Agreement at Royal Mail.
"The months of hard work by the Royal Mail and CWU negotiators helped by me and Acas have now been rewarded by the CWU members' endorsement.
"More hard work now needs to be put in by all to make the transformation real. There are many fine words in the agreement but the parties know that it is deeds not words that now matter.
"Together with Acas, I now look forward to helping the parties start the task of implementation to enable the Royal Mail, CWU and all employees to go forward successfully."
John Taylor, chief executive of Acas, added: "I very much welcome the result of the ballot. Acas was highly involved in helping to resolve this long running dispute, moving Royal Mail and CWU from conflict to constructive joint working."
Postal workers will receive lump sums of around £2,500 and weekly basic pay supplements through consolidation of existing money worth between 2.3% and 5.9%.
The 80-page document also outlines that improved terms will be available for people moving to alternative offices as a result of the changes and a commitment to continue making changes through voluntary means.
Maternity pay will be increased from 18 to 26 weeks and paternity pay from one to two weeks. Staff will be given the opportunity to have more Saturdays off.
Postal workers will receive a 2% pay increase this year, followed by a 1.4% pay rise in 2011 and a 3.5% rise in 2012.
They will also work shorter hours - down from 40 to 39 hours a week - and the Royal Mail has agreed to keep 75% of the workforce as full-time, rather than part-time staff.
In exchange, the union has accepted the large-scale modernisation plan that the Royal Mail says is crucial for its future.
Royal Mail has consistently argued that changes are vital as its core business of delivering letters and parcels is declining by 10% every year. The group also has a £6.8 billion pensions deficit.
