The government recently launched DigiLocker, a free digital vault service which enables storage of sensitive data safely. Still in its beta phase, DigiLocker is the national Digital Locker System that can help you consolidate all your important papers at one place. However, you need to have an Aadhaar card.
One can upload scanned copies, which, if required, can be digitally signed. The locker is also a repository of all your government issued e-documents.These electronic e-documents are uploaded by issuers, government departments or agencies such as CBSE, registrar office, income tax department, etc., in a standard XML format that is compliant to digital locker technical specifications. Right now, you'll only get 10MB of free space, which will be later increased to 1 GB.
DigiLocker is a first from the government. However, private e-locker services have been around for some time now. ICICI bank has a similar e-locker service which customers can use by login in through their internet banking or ICICI Direct account login. Then there are private businesses like Kleeto.in that provide secure online storage for a fee ranging from Rs 200 to Rs 2,000.