IMPORTANT: It is not a key that you put in your microsoft account, you must download office and install it, after that, you will enter the activation key directly in office installed in your pc.
FIRST OF ALL: to avoid any conflict with the installation you must uninstall all the versions already installed on your pc (365, 2016, 2019, etc.) click here to see how: Uninstallation guide.
2- open downloaded file and Click to “start” icon on Office ISO installation folder and wait for installation process it
3- After installation- Click to Start button on your Windows and search : Word or Exel, etc . You need click Word icon to open
4- Click to Account menu
5- Click to Change Product Key
6-enter the key and activate
TO CHANGE THE LANGUAGE
Step 1: Open any Office application. Step 2: Click on “File” in the top left corner. Step 3: Select “Options” from the drop-down menu. Step 4: In the Options window, click on “Language”
Choose desired language and click install. a windows will open (click download)
Install downloaded file and open again word – options – language and choose language and set as default