Since the native app is not supported, you can use these methods to get similar functionality: How to install Microsoft Sticky Notes on windows 2019
: For administrators, it is possible to sideload the Sticky Notes AppX package using PowerShell and DISM. This requires downloading the .AppxBundle and its required frameworks (VCLibs and .NET Native Runtime) from an offline source. Top Alternatives for Server 2019 sticky notes app windows server 2019
Microsoft’s philosophy suggests that "sticky" information on a server should be in a documentation file or a shared Wiki, not a floating yellow box on a specific user's desktop profile. The Workarounds Since the native app is not supported, you
: You can access your synced sticky notes through the web by signing into OneNote for the Web . The Workarounds : You can access your synced
If the server has the installed, you can manually add the Sticky Notes app.