Please how do I download Microsoft office on my MacBook Pro?

I'm not sure if Microsoft still offers Office software for Catalina. Their system requirements say that Microsoft 365 and Office 2021 are supported on the three most recent versions of macOS. Catalina is no longer among those.

https://www.office.com/

https://www.microsoft.com/en-us/microsoft-365/microsoft-office

https://support.microsoft.com/en-us/office/office-2021-and-office-ltsc-for-windows-and-mac-faq-d574cf0b-3ebc-42cf-9035-a3b837e0463c

Just a suggestion as well..maybe don’t take advantage of the Apple’s equivalents: Pages, Numbers and Keynote. Unless you find yourself sharing and collaborating with others that use Office, you may be pleasantly surprised at Apple’s programs. You can even export to send in a Word, Excel format for the times you may find yourself needing to send a document to someone that doesn’t have a Mac and therefore doesn’t have access to the Pages, Numbers or Keynote programs.

Export from Pages, Numbers, or Keynote to Microsoft Word, Excel, PowerPoint, PDF, and more - Apple Support

Another possibility is to install LibreOffice, a Free and Open office suite that will run on Catalina.

https://www.libreoffice.org/