Usually = most informal/casual. "Usually I take the bus, but today I drove a car." Ordinarily = slightly more formal = "Ordinarily, I wouldn't do this." Customarily = most formal. "Koala's customarily eat Eucalyptus leaves. Australians customarily use casual language." They all pretty much mean the same thing = something that is normal, ordinary, or happens a lot. However, customarily is the most formal and not used much in spoken casual conversation. Hope that helps!

Hi Verlsaputha, I hope you are keeping well? Please accept my apologies for the delay in responding. Usually – Casual use/everyday e.g. “I usually go to the shopping centre around the corner.” Ordinarily – a bit more formal but can still be used more frequently e.g. Ordinarily, I use the shortest route to work, however, today I took the freeway. Customarily – formal and relates to certain customs or usual practices e.g. Customarily, we would greet the elders first, before engaging with other members of the family. Hope this assists with further clarification.