I need to delete all info on a mac OS Sierra to get ride of. How do I do this?

Are you going to sell, give away or recycle your Mac? If so follow the instructions in this Apple document: What to do before you sell, give away, or trade in your Mac - Apple Support 

Click here and follow the instructions. If the computer originally shipped with 10.6.8 or earlier, when you reach step 8, use a Mac OS X install DVD instead of the recovery system.

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