If you must pack signed binaries in Azure DevOps, you need to 
<ul>
<li>Output the binaries for signing to a folder, say ‘forSigning’. </li>
<li>Pack the signed binaries without rebuilding.</li>
<li>Sign the NuGet package again. </li>
</ul>
My problem was figuring out how to specify the input and output folders to DotNetPack. It turned out, you can specify the input path with /p:OutputPath and set the output using --output.
Example:
<pre><code>- task: DotNetCoreCLI@2
 displayName: 'DotNetCore Pack'
 inputs: 
 command: 'custom'
 custom: 'pack'
 arguments: '--no-build $(Build.SourcesDirectory)/MyProject.csproj --verbosity normal --output $(Build.SourcesDirectory)\Out /p:OutputPath=$(Build.SourcesDirectory)\forSigning'
</code></pre>

If you must pack signed binaries in Azure DevOps, you need to 

- Output the binaries for signing to a folder, say ‘forSigning’. 
- Pack the signed binaries without rebuilding.
- Sign the NuGet package again. 

My problem was figuring out how to specify the input and output folders to DotNetPack.  It turned out, you can specify the input path with /p:OutputPath and set the output using --output.

Example:

```
- task: DotNetCoreCLI@2
            displayName: 'DotNetCore Pack'
            inputs: 
              command: 'custom'
              custom: 'pack'
              arguments: '--no-build $(Build.SourcesDirectory)/MyProject.csproj --verbosity normal --output $(Build.SourcesDirectory)\Out  /p:OutputPath=$(Build.SourcesDirectory)\forSigning'

         
``` 



Azure DevOps NuGet packing of signed binaries.