Change or Open Your Default Org
Code Builder runs commands against the org that you’ve set as your default org for development. If you use a Dev Hub, your default org is typically a scratch org. In the org development model, it’s usually a sandbox, a Developer Edition (DE) org, or a Trailhead Playground.
To connect to an org, open the Command Palette and run SFDX: Authorize an Org or SFDX: Create a Default Scratch Org. To set or change the org that you’re developing against, in the Code Builder status bar, click the org’s name or the plug icon 
. Then, select a different org, or choose SFDX: Set a Default Org to authorize a new org.
To open your default org so that you can test your changes or use declarative tools, click the open org icon 
in the status bar. Or, open the Command Palette and run SFDX: Open Default Org.
To log out of the default org run SDFX: Log Out from Default Org.