Reset completely, how ?

[soamz]

I have a MacBook pro which has OSX High Sierra.

Now Im selling it someone.

How do I completely factory reset it ?

I did CMD + R and clicked on re install new copy of MAC OS.

It took 1 hour to install and I see everything same apps and same files.

How do i completely factory reset it ?

 

[CoastalOR]

Here is a Apple Support article that tells how to prepare a Mac for sale:
https://support.apple.com/en-us/HT201065

 

[Weaselboy]

I did CMD + R and clicked on re install new copy of MAC OS.

It sounds like you missed the step in the link @CoastalOR provided about erasing the drive before doing the reinstall.

 

[Cordorb]

many forget that there is an Apple manual ( it just is not in the box with the computer )

I use the ibook version - it will help the next user of your computer if you show them where to get the online manual.