Company vs account screen is used to link a company to its respective account. Company and its account, sub account can be assigned here.

Select the OU from the given pick list so that entries related to that OU shall be displayed after the filters all applied.

After selecting the OU, click on the filter button. A popup screen (shown above) appears where you can apply the filters necessary. Click on apply filter button to display all the accounts.

Click on select all to select all the entries in the table and reverse to undo the selections.