On the web, click on the + icon. On mobile devices, in the People screen you can view/ add favorites by clicking on the star icon in the top right. When adding a new favorite, you will see the list of employees of your company, and you can select any member’s phone number to add as a favorite.
On mobile, to delete or rearrange the order of your favorites, enter edit mode. On web, click and hold on the hamburger icon to drag and drop it to the preferred order. Use Remove option from the menu to delete.