In the Desktop version, the Workplace dashboard and Workplace Chat are integrated.
In the mobile versions for iOS and Android, the apps must be downloaded from the respective stores of your phones, they are two different applications: Workplace from Meta and Workplace Chat from Meta.
When you install the applications and log in with your credentials, even though they are two different applications, they are interconnected and share all the same information.
Please proceed to install Workplace and log in with your credentials.