If you are planning to reuse your code, it is better to create your code as libraries and use those libraries in several projects.
https://learn.microsoft.com/en-us/dotnet/standard/class-libraries
If you want the same project to be deployed multiple times, it is possible without duplicating the project itself. You can have as many IIS applications and use the same solution. In general you may change the connection strings and other settings from applicaiton to application.