1 - Go to the SharePoint Site where your file or folder is located.

2 - Select the File or Folder you want to share.

3 - Click on Share.

4 - Click Links Settings.

5 - In the Share window, click the Anyone option.

6 - Select the drop down arrow to give the external user permissions.

7 - Click Apply.

8 - Enter the external email address.

9 - Click Send.