Hello @Susan Hutchinson ,
the following link will provide you with instructions on how to log in to Microsoft 365 with your account on your Apple Mac and download and install the Microsoft 365 desktop applications: https://support.microsoft.com/en-us/office/download-and-install-or-reinstall-microsoft-365-or-office-2021-on-a-pc-or-mac-4414eaaf-0478-48be-9c42-23adc4716658#InstallSteps=Install_on_a_Mac
If this is helpful, please accept the answer. Thank you.