Fax and facts are easily confused words.
The spell-check application of most word processing software programs would not catch a slip-up of these two words. Spell-check is looking for words that aren’t in its dictionary, and words that resemble words in its dictionary, but are possibly spelled wrong. Spell-check isn’t perfect. It doesn’t know and can’t guess what word you wanted, or what word you meant, it can only judge the words on the page. If you used words that are all spelled correctly, it gives you a pass anyway.
Autocorrect suggests words that start with the same letters. It’s suggesting what word you may want to save time, but quite often, its suggestions are pretty off base. They don’t help you out, but they do make you laugh.
Facts (pronounced “fakts”) is a plural noun. It means information is truthful and provable via individual testimony, via documentation, or media footage (CCTV, video, film, etc.), or all of the above.
Fax (pronounced “faks”) is slang for facsimile. It’s a noun. A facsimile is a photocopy of a document electronically transmitted over phone lines. Back in the 1980s-1990s, the fax machine was a staple in every US office.
TRIVIA: A punny sign took off during the 1980s-1990s said “Just the Fax, ma’am.” This was a spoof on a famous catchphrase from the 1950s detective show Dragnet. When Detective Joe Friday was investigating a case, the distraught client would go off on a tangent. He would counter with, “Just the Facts, Ma’am.”
Today fax machines still exist in some workplaces, but they have mostly been replaced by e-documents and online services.
The following story uses both words correctly:
Phyllicia was afraid her account had been compromised at an online store. She called customer service for help. They requested she fill out some information on their site, then fax some supporting documentation, like a scanned image of a photo ID.
“Excuse me, fax? Is this 1989?” she asked.
“No, there’s faxing services online. We’ll be waiting for your information.” the customer service rep said.