Once a charity has registered with HMRC, there are three ways to claim Gift Aid:
Spreadsheet claim, using the Charities Online service via the HMRC registration. Donation lists are provided using spreadsheets, and you can make as many claims as you like.
Direct database claim, for charities that use a compliant donor management software, your software will be able to submit claims directly to the HMRC system. Each claim can be for up to 500,000 donors and you can submit up to one claim per day.
Paper claim, using a form (ChR1) that can be ordered from the HMRC Charities helpline. This can list up to 90 donors, though you can submit as many claims as you like but each must be on an original form, no photocopies.