At its annual conference for software developers, the firm unveiled iCloud Drive, an internet-based storage app, which works on Apple systems and PCs.
In an effort to keep customers using all its technologies, Apple improved integration for calls and messages across its devices.
It also unveiled new mobile and desktop operating systems.
Apple's iMessage app was given extra features, some of which are similar to rival service WhatsApp, recently acquired by Facebook for $19bn (£11.3bn).
Users will be able to easily create and modify group messages, send voice clips with a single swipe, and even create and exchange short video clips.
The ability to send and receive text messages across all Apple devices was also introduced.
Jan Koum, WhatsApp's co-founder, reacted to Apple's announcement by tweeting:
"Very flattering to see Apple "borrow" numerous WhatsApp features into iMessage in iOS 8 #innovation"
Apple also introduced HealthKit software that works with third-party wearable health devices.
A parallel app, called Health, measures users' personalised healthcare statistics, and even contacts their hospital directly if it notices irregularities.
"The announcements represent an ambitious move to diversify the Apple ecosystem into a number of new segments," said Geoff Blaber, an analyst at the CCS Insight consultancy.
"Critics will complain of no new devices but the Worldwide Developers Conference creates the foundation for the products [Apple chief executive] Tim Cook is promising in the second half of the year."
iCloud Drive allows users to save any type of file on the firm's remote servers and then access it via an iOS device, Mac computer or Windows PC.
Users do not have to pay an extra fee unless they want use more than five gigabytes of storage.
That is more than Dropbox's 2GB sign-up allowance, but less than Google Drive's 15GB provision, Microsoft One Drive's 7GB limit and Box's 10GB cap.
Apple's service includes the ability to email attachments of up to 5GB, something also offered by Dropbox and HighTail - a specialist data-sharing facility.
However, Apple made no mention of iCloud Drive being accessible via Android, unlike the other services that offer apps via Google's Play store.
"iCloud drive [is a] big shot at consumer Dropbox, if it works well,"tweeted Benedict Evans, an analyst at venture capital firm Andreessen Horowitz - a nod to the fact that Apple has faced problems with its online services in the past.
Former chief executive Steve Jobs had previously attempted to buy Dropbox, reportedly warning its founders that he intended to go after the same market when they refused.
Automated homes
The latest version of Apple's operating system for desktops and laptops, entitled OS X 10.10 Yosemite, features a flattened design, and closer integration with other Apple devices, allowing users to make and receive calls and text messages from their iPhone on their desktops or laptops.
Like its predecessor, Mavericks, OS X Yosemite will be made available as a free update to existing Mac users.
Apple boss Tim Cook also showcased the tech giant's forthcoming mobile operating system, iOS 8, and emphasised cross-device integration. One feature, Handoff, allows users to start a task on one device and instantly pick it up on another.
Apple's software engineering vice-president, Craig Federighi, also unveiled HomeKit, which allows users to control their home environment with smartphones.
"Only your iPhone can open your garage door, or unlock your door," he told the audience in San Francisco.
"With Siri integration you can say something like 'get ready for bed' and be assured that your garage door is closed, your door is locked, the thermostat is lowered and your lights are dimmed."
Source: BBC News
