Hello, Yussif Mohammed Bawa.
Welcome to Microsoft Community!
You can purchase Microsoft Complete, via the Surface App, within 45 days of device purchase:
Microsoft Complete - Protection Plan for your Surface or Xbox- Microsoft
Or you can purchase up to 3 years of Microsoft Complete service by visiting the site directly below:
Buy Microsoft Complete for Surface Laptop with Accidental Damage Coverage (3-Year) - Microsoft Store
I hope this information helps.
Please don't hesitate to let us know if you have any doubts while using your Surface.
Best Regards.
Leo.L - Microsoft Community Support Specialist