Invitation is a request (spoken or written) to go to a place or do something.
There are two types of invitation :
a. Formal Invitation
Formal invitation is usually originate from Institutes, Companies, and a kind of it. Normally, formal invitation is written invitation.
b. Informal Invitation
Informal invitation is personal invitation given to a friend, family, etc. Informal invitation can be written invitation and verbal invitation.
¯ Extending Expressions
§ Please come inside !
§ Would you come to my brother’s party tomorrow?
§ Can you drop by my house after school?
§ If you’re not busy, please come to my cafĂ©.
§ Would you like to go out with me this evening?