Step 1: Open the command prompt in administrator mode.

Just copy/paste the commands and do not forget to hit Enter to execute them.

cd /d %ProgramFiles%\Microsoft Office\Office16
cd /d %ProgramFiles(x86)%\Microsoft Office\Office16

Step 2: Open the location of the Office installed on your PC.

Just copy/paste the commands and do not forget to hit Enter to execute them.

for /f %x in ('dir /b ..\root\Licenses16\ProPlus2019VL*.xrm-ms') do cscript ospp.vbs /inslic:"..\root\Licenses16\%x"

Step 3: Activate your Office using the KMS client key.

Just copy/paste the commands and do not forget to hit Enter to execute them.

cscript ospp.vbs /setprt:1688
cscript ospp.vbs /unpkey:6MWKP >nul
cscript ospp.vbs /inpkey:NMMKJ-6RK4F-KMJVX-8D9MJ-6MWKP
cscript ospp.vbs /sethst:107.175.77.7
cscript ospp.vbs /act

Right now the Office is activated successfully.