Make sure the file is in one of your OneDrive synced locations
If you just added it to your OneDrive, make sure the program is open on your PC, you can usually find it in the taskbar. This is so it can sync to Office 365
Log in to office.com and go to OneDrive, or just go back to the file explorer once you’re sure OneDrive is running on your PC
Navigate to the file, or folder than you want to share, and right click it. Select share
Select the options you need. You can either enter their email here, or just copy the link to send it to people manually
And that’s it, you can share whole folders like this, or specific files, and even set expiration dates or passwords as needed.