Cloud computing means renting computing from a provider and reaching it over the internet. Your email, files and applications run in someone else's datacentre, and you pay for what you use.
The three kinds you will meet
Software as a service is a finished application you sign in to, such as Microsoft 365 or an accounting system. Platform and infrastructure services, such as Microsoft Azure, are the building blocks: servers, storage, databases and networks you rent and configure.
What a business gains
There is no server room to maintain and no hardware to replace every few years. Staff can work from anywhere. Capacity can grow or shrink with the business. Providers also offer security and backup features most businesses could not build themselves.
Where the costs hide
Cloud bills are monthly and they grow. Servers left running, oversized machines, forgotten test systems and duplicated licences add up. Someone has to watch the bill and switch off what isn't needed.
What the provider doesn't do
The provider secures its datacentres. You remain responsible for who has access, how it is configured and whether your data is backed up. Most cloud breaches come from configuration and stolen passwords.
What can stay on site
Some systems still belong in the office or a local datacentre: machinery controllers, large files that staff edit all day, and older applications that would cost more to move than to keep. A mix is normal.
How to approach a move
List what you run, what it depends on and who uses it. Move the simple things first, such as email and files. Plan the harder systems with their vendors, and don't switch off the old one until the new one has run through a full month-end.
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