First and foremost, hit the Search tab located on your screen somewhere besides the option of the Start tab.
It will be located at the bottom left edge of the screen.
Then, you have to enter any application name,
Now make sure it should be the part of the existing Office suite that you are going to launch.
It might be anything such as MS Word, MS Excel, MS Access, etc.
Next, you have to enter the activation code into the relevant activation field.
This is a necessary task for activating the product.
In case If you purchase office365 using office.com/setup then It will be on your product package or email.
Now, license terms and conditions wizard will show up on the screen that you are using.
At the bottom portion of the window, you have to hit the Accept tab.
This will certify your operation that you have read all the license agreements for the said subscription and activation process.
Once it is done, after a while, you will get the MS Office activated.