@Leland Wallace answer is completely correct to "remove" macOS Server but here is how to completely remove everything related to macOS Server.

Note: This will remove all data relevant, including, but not limited to, Web Site files, Wiki Files, Configuration Files. This will basically leave your computer as it was before you installed macOS Server.

1. Right click on the Server Application and click "Show Package Contents"

2. Navigate to /Applications/Server.app/Contents/ServerRoot/usr/share/devicemgr/backen

3. Double click on wipeDB.sh. This should open it in terminal.

4. Enter your admin password (or root password if setup)

5. Then follow @Leland Wallace answer and remove the Server application

@Leland Wallace answer is completely correct to "remove" macOS Server but here is how to completely remove everything related to macOS Server.

Note: This will remove all data relevant, including, but not limited to, Web Site files, Wiki Files, Configuration Files. This will basically leave your computer as it was before you installed macOS Server.

1. Right click on the Server Application and click "Show Package Contents"

2. Navigate to /Applications/Server.app/Contents/ServerRoot/usr/share/devicemgr/backend

3. Double click on wipeDB.sh. This should open it in terminal.

4. Enter your admin password (or root password if setup)

5. Alternately: in terminal: sudo ./Applications/Server.app/Contents/ServerRoot/usr/share/devicemgr/backend/wipeDB.sh

6. Then follow @Leland Wallace answer and remove the Server application