Sharepoint Online: How To Share a File or Folder
If a user only needs access to a single file or folder, then you (as a member of the sharepoint site) can share the folder with the user, similar to how you would share via OneDrive:
When signed into Sharepoint site in Web Browser:
Hover over the file or folder you’d like to share, click the three dots, choose Share:
Type the users email address (or leave empty if you need just a link to copy), then click the Gear Icon:

On the 'Link settings' popup, choose whether the user is an HFA user (with @hfahawaii.com email address) or choose "Peoplend assign the ‘can Edit’ permissions to allow the user to upload documents, or ‘can View’ permissions to only allow the user to view, but not edit:

Alternatively, on some Sharepoint sites, you are allowed to create Anonymous or "Anyone" links that can be opened by users with or without @hfahawaii.com email addresses. To do this, simply check the Anyone option. The expiration date is automatically required for 90 days (default) for Anonymous links for security purposes.
Click Apply.
Back on the Share popup, click Copy Link to copy the link (with the link settings you just set) to paste into an email (or Teams, etc), or click Send to send an invitation to any email addresses you included in the Share panel.
To manage all the Share Links you've made for a certain item:
When you hover over the item, click the three dots (...) then click "Manage Access". On the Links tab, you'll see how many of these Share Links exist for any given item, and you can revoke them or create another link with different share settings.