Hi there
Salutations and
greetings are polite ways of saying hello and can be used to begin a message or letter. Both indicate a gesture of welcome and
can also be used to express goodwill to another. I feel that
salutations is a more formal expression than
greetings.
Other less formal words that we use to begin emails/letters etc are : hi, hello.
Hope this helps!
Deborah ESL