You have to check if your WordPress site is using a cache plugin (such as WP Super Cache) or a CDN like CloudFlare or Amazon CloudFront. In that case, you can manually clean the cache in order to see those changes.
You can also force refresh without cache, that will make you be able to look at the changes you just did, however, keep it mind that until the cache is clean, other visitors won’t be able to see the updated version.