Activate Windows 10 / 11

slmgr /ipk <license-key>
slmgr /skms <kms.server.host>
slmgr /ato

Activate Office 2021

if exist "%ProgramFiles(x86)%" cd /d %ProgramFiles(x86)%\\Microsoft Office\\Office16
if exist "%ProgramFiles%" cd /d %ProgramFiles%\\Microsoft Office\\Office16
for /f %x in ('dir /b ..\\root\\Licenses16\\ProPlus2021VL_KMS*.xrm-ms') do cscript ospp.vbs /inslic:"..\\root\\Licenses16\\%x"
cscript ospp.vbs /setprt:1688
cscript ospp.vbs /unpkey:6F7TH >nul
cscript ospp.vbs /inpkey:<license-key>
cscript ospp.vbs /sethst:<kms.server.host>
cscript ospp.vbs /act