Formal language does not make use of contractions, colloquialisms, or first person pronouns like “I” or “we.” Informal

Formal language does not make use of contractions, colloquialisms, or first person pronouns like “I” or “we.”
Informal language, on the other hand, is much more spontaneous and casual. This is the type of language used when communicating with friends or family members and can be used when either writing or speaking.
Informal speech may include slang words such as 'lit', 'shook' and 'squad'. People speaking informally will typically use contractions to save time, choosing to say 'haven't' rather than 'have not'. For instance: “Cheers for ringing, Dude.
Informal style .The style of writing is said to be informal if the words used are common and everyday words and the sentence structure is casual and friendly.

Informal	Formal
lots of/ a lot of	much, many
tons of, heaps of	large quantities of, a number of
totally	completely, strongly
really, very	definitely

Types of formal communication
· Memos.
· Intranet.
· Meetings.
· Conferences.
· Formal One-on-Ones.
· Bulletin Boards.
· Handouts.
· Letters.
Informal channel of communication is an unofficial and unstructured channel which is not prescribed by the organization but exists due to personal and social needs of people working in an organization. Information that passes through informal means is not official but may be merely rumors or gossips.