Microsoft has officially announced Windows 11 ready for widespread deployment. This means that all compatible computers running Windows 10 builds 2004 and newer now offer a free update bar in the "Update Center".
However, if you are planning an upgrade, first you need to make sure that your computer meets the minimum requirements of Windows 11. They are stricter than previous system updates: the most problematic for users was the need for the TPM 2.0 module. You can check compatibility in automatic mode via PC Health Check.
At the same time, upgrading to Windows 11 is not mandatory: the popular Windows 10 will continue to be supported until at least 2025.