If the pgAdmin menu Tools -> Server Configuration is disabled, you need to enable the administrative extension.  Please follow these steps:

1. open pgAdmin

2. open your server -> "Databases" node and select the "postgres" database

3. click the SQL button

4. paste the following SQL command into the query editor:


5. run the script by either pressing F5 or clicking the "play" button

6. close pgAdmin

7. open the Services app and restart the PostgreSQL service (for Spire 3 it will be the service called "spire-postgresql-10") [note that end-users shouldn't be using the system (i.e. have open unsaved data) at the time of service restarts]

8. run pgAdmin again to verify the changes