Windows 10 automatically downloads and installs updates as soon as they appear.
To stop this, you can "pause" the installation of updates for up to 35 days.
1. Open Settings - > Update and Security - > Windows Update.
2. Click "Install Updates for 7 days".
3. Click this button again to increase the period.
When you click up to 35 days, the option will turn gray - this is the maximum value.