Letter written on 7 Aug 1969 (to Kapil)
Osho wrote many letters to Ma Kusum Bharti and her husband Kapil, then of Ludhiana. This appears to be the only one addressed to Kapil specifically, though he was always mentioned in the others. All but a few were published in Prem Ke Swar (प्रेम के स्वर). The wiki has images of all but one of those published in PKS, plus a few more unpublished ones, plus one in English published in The Gateless Gate.
This letter is dated 7th August 1969. It was one of those published in Prem Ke Swar (प्रेम के स्वर), as letter #3. The letterhead was a typical one of those days, showing a simple all-lower-case "acharya rajneesh" at "kamala nehru nagar" in "jabalapur (m. p.)", with his 4-digit phone number and a two-colour Jeevan Jagriti Kendra logo.
Kamla Nehru Nagar : Jabalpur (M.P.). Phone: 2957
रजनीश के प्रणाम