Hello,
If you go to Settings > Windows Update, do you see an update that says something like "Windows 11, 23H2/24H2 is available"? If so, download and install 23H2 or 24H2.
The other method is to use one of the three tools Microsoft provides to you to upgrade your PC.
You can use the Windows 11 Installation Assistant, the Windows 11 ISO, or the Media Creation Tool. All three of these options will get you to Windows 11, version 24H2.
To use the Windows 11 Installation Assistant, download theWindows 11 Installation Assistant and then run it. You should see some prompts telling you about Windows 11 and what it'll install. Let it download and install 24H2.
To use the Windows 11 Media Creation Tool, download the Windows 11 Media Creation Tool, and run the MCT. Once it finishes loading, push "Upgrade this PC Now". Let the MCT install the Windows 11 installation files, and then let it check for updates, and then let it install Windows 11.
To use the Windows 11 ISO, download the Windows 11 ISO, (you can find it here, scroll down to where you see ISO for Windows 11 x64 devices), mount it, and then run setup.exe (if you see a UAC prompt, push yes). Follow the prompts on-screen and then let setup.exe update and install Windows 11, 24H2.
All of these steps will eventually get you to 24H2 and will take a while to download and install. It's best to do this at night when you're not doing anything important. Just make sure to save your files before you start.
Hope this helps, and if you have any questions, don't hesitate to let me know!