Invitation ( Written )

Most spore invitation are in the farm of question they often begin with will,would,would you like to,would you care to,etc

Offering invitation:
->Would you like to come to the restaurant this evening?
->Will you join us?
->Would you care to have dinner with us tonight?
->Could you come to a party at my place tomorrow?
->I wander whether you would care to come on a picnic with us next week?

Accepting invitation:
->Yes,I do love very much.
->Thank you.
->Yes, with pleasure. 

Refusing: 
->If you do not mind,i do rather not.
->Thank you,I am busy, may be next time.
->I have got another appointment.
->I am sorry.
->I have lost to work to do.

Invitation Verbal

Example:

We want to invite you to come to our house

Can you come to my restaurant?

Are you free tonight?

Accepting:

I like that

That sounds good

Thank you for inviting

Refusing:

I like that but I can not.

I am very sorry for not able to come.

Sorry, I am very busy.