visitor visa letter

[musa]

hi,
my sister and my brother are 27 and 25 years old and they applied for visitor visa to come to my other brothers wedding, who lives here now, and i want to send them a letter to say that i will sposor them here.. but i dont know how to write, can any body help me please!!
thanks

[VisaChief001]

sponsor guarantee should be on I-134 Affidavit of Support not any letter.

[musa]

thanks for the reply, but i know that i should send them a letter saying that they will leave before the expiration date and that i will support them finanically , but i dont know the format of this letter or who should i address to!! if any body has a sample or has experice in that please let me know...
thanks

[dahlia]

https://www.immihelp.com/usa-visitors-visa-sponsor-documents/

[musa]

thank you so much