If you want to share a folder with sb. on your LAN please right click on the folder and find Properties.
Find the Sharing tab on the pop-up conv. panel.
Press Advanced sharing button and check Share this folder. Press Permissions button and Allow Full control to Everyone.

Because remote user is not known in your system you need to create a user for this purpose and need to share the credential with your counterpart.
1.) Run compmgmt.msc from Start menu and navigate yourself to Local Users and Groups.
2.) Create a user with password and send it your counterpart.
3.) If he\she tries to open the folder Windows Authentication panel pops up where the account will be able to log on and browse the folder.
*.) If you need to grant write privilege to this user please navigate back under the folder properties and find the security tab. Change the privilege of the USER group.
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