Additionally, send a copy of your marriage invitation to show that he is only coming for a purpose. I would like to invite you to the United States of America to stay with us for three months.It would be very nice to have you with us. To help you extend invitations, we have samples on how to write a letter to your friend to invite to your brother's wedding for you. I have attached the wedding invitation to this letter for your reference. I hope you understand and approve my leave request. All words should be spelled out on invitations, enclosure cards, and envelopes, no matter how informal your wedding is. It gives me immense pleasure to cordially Invite you and your family on the auspicious occasion of my brother's marriage.