I need help

The usual or correct path probably did not occur with your Possession of this MacBook;

this would set the tone of actual Ownership. And predates present action, outlined here:

• What to do before you sell, give away, or trade in your Mac - Apple Support

https://support.apple.com/en-us/HT201065

#7: instructions, is where you'd need to be -- if not already set up ahead of this issue..

"The best way to restore your Mac to factory settings is to erase your hard drive and reinstall macOS."

"..After macOS installation is complete, the Mac restarts to a setup

assistant that asks you to choose a country or region. To leave the Mac

in an out-of-box state, don't continue setup. Instead, press Command-Q

to shut down the Mac. When the new owner turns on the Mac, the setup

assistant guides them through the setup process..."

A back-study of the status of this macbook is not addressed here;

so that is where it should have been, on arrival in your possession.

And to save any works you may have in that Mac, needs saving to

an external USB drive. A backup. Then if there's no Admin PW lock

or other firmware security, you may proceed. As the Admin/owner.

hawraa49:

While there are a few ways to attempt to find lost password,

these usually require the owner to have set one first. This has

a definite process; often enough without valid clues, cannot

proceed and requires luck, magic; a trail of breadcrumbs, etc.

• 4 Ways to Reset a Lost Admin Password on macOS X - wikiHow

https://www.wikihow.com/Reset-a-Lost-Admin-Password-on-Mac-OS-X

• If you can't reset your Mac login password - Apple Support

https://support.apple.com/en-us/HT212190

• Reset a Lost OS X Account Password | General, System Pref, Terminal, Utilities | OS X Tips

http://www.macosxtips.co.uk/index_files/reset-lost-os-x-account-password.php

• Three Ways to Reset a Lost Admin Password in High Sierra - TidBITS

https://tidbits.com/2018/07/05/three-ways-to-reset-a-lost-admin-password-in-high-sierra/

IF your MacBook7.1 (13-inch Mid 2010) is generally identified correctly,

that is among last ones which shipped with Installer DVD media.

[Try macOS Recovery, which could work only if you/previous owner

had used last supported internet-based system; to access Utilities.]

Original OS Mac OS X 10.6.3 (10D2162), 10.6.8 ~ from Install/Restore media

Later OS Mac OS X 10.6.4 (10F2108), 10.6.8 | 10.7.2 (11C74), 10.7.5.

Maximum OS macOS 10.13.6 (17G65) ~ from Internet Download install.

While sometimes possible, usually after upgrade to later MacOS X

may not work to restore 'last supported' system. (Due to Firmware

or low-level change? perhaps file system change from HFS+, too?)

• Reset Mac OS X User Password Without CD with Command Line | older

https://brakertech.com/reset-mac-os-x-admin-user-password-without-cd-disk/

There are way too many random elements that may apply; if you

had clues or notes to follow; or even suitable installer media to

try. Any of these could wipe whatever you had on the MacBook.