A few simple steps teach you how to format the computer by yourself

Step 1: Enter settings in search, and then click Settings

Step 2: Select Update & Security

Step 3: Choose Recovery next to it

Step 4: Then click Get Started in the Reset This PC option

Step 5: Then a window will pop up with two options

i) keep my files
Choose this, your files, photos, etc. will not be deleted, but will be saved in the original location.
ii) Remove everthing
By choosing this, it will delete everything, including files, photos, etc.

It must be noted that both options will clear the software you installed yourself, so you must install it yourself after reset!