The new service that will enable charities to file Gift Aid claims online will come into force in April, HM Revenue & Customs has announced.
The system, called Charities Online, will replace the existing claim forms, although HMRC will introduce a new form that will allow charities to submit applications on paper.
The new system will also require some changes to the information that must be submitted to HMRC.
Charities will now need to provide donors' addresses in addition to their name, date of donation and the amount given.
The Charity Tax Group welcomed the changes, but said the timescale to introduce them was tight.
John Hemming, chair of the CTG, said in a statement that the changes would benefit charities and were "the most important practical change for Gift Aid for many years". But he said the transition would "not be straightforward for charities".
"The new system, once in place, should reduce the administrative burden faced by charities and speed up the payment of much-needed funds for the charity sector," he said. "Nevertheless, CTG has repeatedly expressed concerns that the timetable is very challenging. Charities need to consider as soon as possible how Gift Aid online will affect them."
He said charities should make sure they were up to date with their Gift Aid claims before the new system was introduced, particularly if Gift Aid formed an important part of their cash flow.
"We are particularly concerned that the residual paper form may end up being cumbersome and impractical and not be a credible option for most charities," he said. "It is vital that charities make preparations now to move their Gift Aid Claims online."