Step 1: Open the Main Menu (Click the Gear Icon at the right corner)

Step 2: Click the "Add/Switch Accounts" link to list the connected Xero Companies. 

 Step 3: Select the needed account. 

Switch Xero company using Company Menu

Step 1: You can also click the company name located at the top of the page.

Step 2: It will open the side menu to list the connected accounts.

Step 3: Select the needed account