where to download office 2019 professional plus?

hi dawei4321​ If you already have a valid Office 2019 Professional Plus license, the installation method depends on how the license was obtained.

Office 2019 Professional Plus is generally a volume licensing edition, so if it was provided through an organization, the installation files would normally come through the organization's Microsoft licensing/deployment channel.

If you purchased a standalone Office 2019 license, check the Microsoft account associated with the original purchase or activation to see if the installation option is available there.

I would also recommend avoiding third-party download sites, as unofficial Office installers can be modified or unsafe.

If you can share whether your Office 2019 Professional Plus license is retail, volume license, or provided by an organization, and whether you still have the product key, the community can suggest the appropriate installation method.