Press Windows Key+C and open Settings followed by Change PC Settings. Next click Update and Recovery on left pane. Choose download option and allow the PC update to begin. In case you are a Windows 7 user begin by clicking on Start and type Update in the query/search box. Next click on the option Windows Update. On the pane at the left, click on Check for Updates. Finally, select All Updates and finally, Install Updates.
Once you perform these steps, the Get Windows 10 application will be downloaded on the computer. Open the same and select Reserve Your Free Upgrade option. Once asked, key in your email address to get the confirmation for this reservation.