Advertise, advertisement
Advertise
Say: AD-ver-tize. To tell people about a product.
The bakery will advertise its new cakes.
Advertisement
Say: ad-VER-tis-ment (British). A notice selling something.
Sana saw an advertisement for a painting class.
Remember: Advertise starts with AD. British advertisement moves to VER; American English says ad-ver-TIZE-ment. Both are correct — just be consistent.