Introduction
The files you store on a SharePoint site are usually available to everyone with permissions to the site, but you may want to share specific files or folders with people who don't otherwise have access to the site. When you share files and folders, you can decide whether to let people edit or just view them. You can see who a SharePoint file is shared with, and stop sharing SharePoint files or folders, or change permissions, at any time.
Notes:
To share OneDrive files and folders, check out Share OneDrive files and folders.
You can also share the entire site.
Your sharing experience may look slightly different than the steps and screenshots below, but the information will still help you share files and folders.
File or folder sharing from modern experience breaks the inheritance at the list/library level.
Instructions
Detailed, easy to follow instructions from Microsoft, to include "Share with specific people" and "share by using copy link" can be found at:
Share SharePoint files or folders