Hi @daryush salahshur ,
The required version of sharepoint is 2016. We are unable to create sharepoint 2016 empty project in sharepoint 2019. I would introduce sharepoint framework to you if you want create custom web part in sharepoint 2019. Here is the link of document
https://learn.microsoft.com/en-us/sharepoint/dev/spfx/sharepoint-framework-overview
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