Every Apple user is entitled to 5GB of free iCloud storage. It can be upgraded from any device if you need extra space.

On your iOS device

  1. Go to Settings -> tap Your Name -> iCloud -> Manage Storage or iCloud Storage.
  2. Tap Buy More Storage or Change Storage Plan.
  3. Chose a plan that fits your needs.
  4. Tap Buy -> follow the onscreen instructions.

On your Mac

  1. Go to Apple menu -> System Preferences -> your Apple ID. On macOS Mojave or earlier, you don’t need to click Apple ID. 
  2. Click iCloud.
  3. Click Manage in the lower-right corner of the window.
  4. Click Change Storage Plan or Buy More Storage. Here you can choose a suitable plan.
  5. Click Next -> enter your Apple ID password.

On your Windows PC

  1. Open iCloud for Windows.
  2. Click Storage -> Change Storage Plan.
  3. Choose a suitable plan -> click Next.
  4. Enter your Apple ID password.
  5. Click Buy.

It's good to know: iCloud storage is not intended to be used as a substitute for your local (internal) storage on your iOS device. So, if you receive a message that your iPhone is almost full, buying more iCloud storage doesn’t solve that problem.

Good luck!