Qt doesn't provide a deployment packaging tool for Windows so you have to use a third party tool. I have listed a couple of the commonly used ones. How you use them is a matter for their manuals and tutorials. In short:
- Build and test your Qt project
- Work out what you need to deploy: Deploying Qt Applications
- Write a script for your installer generator of choice
- Run your installer generator of choice to build your installer.
- Profit
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