Between friends, it is often informal. For business, it should always be formal.
An informative email will be in the form of an email and have information about a subject
Email is so quick easy fast and it's cheep
informal, personal of friendly letter are often letter to family member or friends.
It means write to me, an informal invitation to write a letter, email, postcard etc.
the difference between these is that formal email is writing an email in a polite way and informal email is using Geordie language, e.g you alreet pet hows u doing? - this is an informal email as they are using Geordie language and some people will not like the way that people speak.
Etiquette for email is most often referred to as netiquette.
The advantages of a domain based email such as tiscali is 1&1 hosting, and the ability to have a quick, informal source for personal email and personal information sharing.
LOL: Laugh Out Loud
There are many types of informal communications: email, fax, note, personal letter, chat with a friend, water cooler gossip and phone calls, to name just a few.
"Dear Friends" might work.
An informal theatre space can allow the guests to relax while they watch their movie. They often are more interested in the movie if the theatre is informal, as they feel comfortable and ready to focus.
Cual es su correo electronico?- formal way me pasas tu email? -informal way