23H2 update is coming soon.
But you are able to update your OS to 23H2 build 2428 right now. I would like to show how to do that manually.
Download 3 files below:
SSU-22621.2351-x64.msu 
Windows11.0-KB5030310-x64.cab 
Windows11.0-KB5030310-x64.psf 

Then download Update Utility by abbodi1406: 
W10UI_10.32.zip 

Unzip the W10UI_10.32.zip file into the created W10UI_10.32 folder and copy all three files downloaded earlier into this folder. Run the W10UI.cmd file with administrator rights - a command prompt window will open. Press the 0 (zero) key to start the update, and when finished, restart your PC. 

Next step: download file:
windows11.0-kb5027397-x64
Unpack the archive and run the file windows11.0-kb5027397-x64.msu, after the update is completed, restart the PC again.
After rebooting, the version of your OS should be 23H2, build 22631.2428, you will see the Copilot Preview icon in the taskbar.