Here are the complete steps, adapted from Stefan Timovski's article on [How to Create SQL Server Management Studio 18 (SSMS) Extension][1]

1. **Install [Visual Studio 2017][2] with *Extensions Toolkit***

 If you're not sure you have the extensions toolkit, you can open the Visual Studio Installer and modify your current install to make sure you have extensions installed

 [![Visual Studio Installer][3]][3]  
 [![Visual Studio Extension Development][4]][4]

2. **Create New Extension Project**

 Go to File New Project (<kbd>Ctrl</kbd> + <kbd>Shift</kbd> + <kbd>N</kbd>)

 [![File > New > Project][5]][5]

  Choose Extensibility > VIX Project

 [![Extensibility > VSIX Project][6]][6]

 If you don't have these options, go make sure you did step 1

3. **Add a New Command Item**

 Add a new item (<kbd>Ctrl</kbd> + <kbd>Shift</kbd> + <kbd>A</kbd>)

 [![Add New Item][7]][7]

 Select Extensibility and just for demo purposes grab a custom command

 [![Extensibility > Custom Command][8]][8]

4. **Debug in Visual Studio**

  The command file will add a menu item to Tools > Invoke *Command1*. If you hit debug, Visual Studio will launch a Debuggable instance, fully loaded with your current extension.  Hit play or hit <kbd>F5</kbd>

  The first time may take a minute to boot-up, but it should go faster thereafter

  [![Launch Debug][9]][9]

  The click event handled in located in *Command1*.cs > `Execute`, and you can add breakpoints.

  [![Debugger Breakpoint][10]][10]

  Here's the working message box

  [![Callback][11]][11]

5. **Get filepath for SSMS**

  The default installation path for SSMS 18 should be:

        C:\Program Files (x86)\Microsoft SQL Server Management Studio 18\Common7\IDE\Ssms.exe

 If it's not there, to identify the startup location of any app, you can <kbd>Shift</kbd> + Right Clicking on the app icon and select "Open file location"

  [![SSMS Location][12]][12]

6. **Set Launch to SSMS**

 Open up the project properties in VS (<kbd>Alt</kbd> + <kbd>Enter</kbd>)

  [![Project Properties][13]][13]

  Go to **Debug** > **Start External Program** and paste in the path

  [![Debug > Start External Program][14]][14]

  Remove the command line args as they're no longer applicable to SSMS

7. **Set Deploy VSIX to SSMS**


  The "Extensions" subdirectory should be in the same directory as SSMS. Also, add an extra folder with your project name like this

        C:\Program Files (x86)\Microsoft SQL Server Management Studio 18\Common7\IDE\Extensions\VSIXProject1

  Go to **VSIX** > and select "**Copy VSIX content to the following location**"

  [![VSIX Copy][15]][15]

8. **Set Permissions**

  Lastly, in order to programmatically invoke any apps on C Drive, you'll need admin privileges, so you need to open Visual Studio in Admin Mode.  You can do that by right clicking on the application like this

  [![Run As Admin][16]][16]

9. **Hit Run & Debug**

  Presto! Blamo! Your extension should now be running SSMS

  [![SSMS Debugger][17]][17]

### Further Reading

Historically, each extension needed to be whitelisted, but according to the [release notes for SSMS 18][18], one big change (for the better) is 

> Package IDs no longer needed to develop SSMS Extensions  
> In the past, SSMS was selectively loading only well-known packages, thus requiring developers to register their own package. This is no longer the case.


Since SSMS 18 uses the *Visual Studio 2017 Isolated Shell*, many of the extension developer documentation is available under the [Visual Studio Extension Docs][19]


  [1]: https://www.codeproject.com/Articles/1377559/How-to-Create-SQL-Server-Management-Studio-18-SSMS
  [2]: https://visualstudio.microsoft.com/downloads/
  [3]: https://i.stack.imgur.com/KM1FS.png
  [4]: https://i.stack.imgur.com/YTTcX.png
  [5]: https://i.stack.imgur.com/GTM5p.png
  [6]: https://i.stack.imgur.com/Y9YmZ.png
  [7]: https://i.stack.imgur.com/Qg2Xy.png
  [8]: https://i.stack.imgur.com/RA12s.png
  [9]: https://i.stack.imgur.com/eUa1Q.png
  [10]: https://i.stack.imgur.com/R9x2b.png
  [11]: https://i.stack.imgur.com/2azx4.png
  [12]: https://i.stack.imgur.com/nCvLM.png
  [13]: https://i.stack.imgur.com/W2CuZ.png
  [14]: https://i.stack.imgur.com/uLXFx.png
  [15]: https://i.stack.imgur.com/GVXi9.png
  [16]: https://i.stack.imgur.com/t2OFU.png
  [17]: https://i.stack.imgur.com/tshEu.png
  [18]: https://learn.microsoft.com/en-us/sql/ssms/release-notes-ssms?view=sql-server-2017#180-preview---cumulative-changelog-through-rc1
  [19]:https://learn.microsoft.com/en-in/visualstudio/extensibility/extensibility-hello-world?view=vs-2019

[SQL Server Management Studio 18 RC1][0] became available March 28, 2018

This question has already been asked [for SSMS 17][1], but there are slight variations when authoring extensions for different releases of SQL Server Management Studio.

**What are the steps to getting a Hello World application up an running in SSMS 2019?**



[0]: https://learn.microsoft.com/en-us/sql/ssms/download-sql-server-management-studio-ssms?view=sql-server-2017
[1]: https://stackoverflow.com/q/47240020/1366033