How do I share a big file with someone outside the company?

Email attachments fail above about 20 to 25 MB depending on both mail systems, and even when they work they create copies you no longer control.

The right method, which you already pay for:

• Right click the file in OneDrive or SharePoint and choose share
• Set the link for specific people rather than anyone with the link, when the content matters
• Set an expiry date, particularly for anything client related
• Send the link rather than the file

Why it is better: the recipient always gets the current version, you can revoke access later, and you can see that it was accessed. None of that is true of an attachment.

What to avoid: personal Dropbox, WeTransfer, or Google Drive accounts for company files. It works, which is why people do it, but the file is now outside anything you control or can revoke, and if it contains client data that may be a problem you have to explain later.

If your staff are routinely reaching for consumer tools, that usually means sharing has been locked down too far or never explained. Both are worth fixing, because people will always route around friction.