Clothes is a plural noun with no singular — you cannot say "a clothe". Clothing is uncountable and treats the category as a mass: "protective clothing". Both are correct; clothing is slightly more formal and is the one used in general or technical statements.
The core difference
The difference is grammatical rather than a matter of meaning.
- clothes — plural, takes a plural verb: My clothes are wet. No singular form exists.
- clothing — uncountable, takes a singular verb: Protective clothing is required.
Counting them
Neither word can be counted directly — "three clothings" and "three clothes" are both wrong. English supplies items of clothing, garments or articles of clothing for that job.
Register
Clothing is usual in signage, regulation and retail categories; clothes is the everyday word. "Take your clothes off" is natural; "remove your clothing" sounds official, which is exactly why notices use it.
Frequently asked questions
Is clothes singular or plural?
Plural, always. It takes a plural verb and has no singular form — "a clothe" is not a word.
Can I say "a clothing"?
No. Clothing is uncountable. Use an item of clothing or a garment.
Which is more formal?
Clothing. It is the usual choice in regulations, signage and retail categories, while clothes is the everyday word.