Is a divorce counted if the husband writes to his wife, "You are divorced," after having been in seclusion with her without her family's knowledge, and what is the way to take her back, and is a new marriage contract necessary, or is it sufficient to return her to his عصمة (marital bond) with two witnesses?

If you have consummated your marriage with your wife and divorced her with less than three pronouncements, you have the right to take her back as long as she is within her waiting period (iddah), without a new marriage contract. Divorce written down without being verbally pronounced does not take effect unless you intended it, according to the majority of scholars. If you write a divorce statement to your wife, intending it, one divorce pronouncement has occurred, and you have the right to take her back as long as she is within her waiting period, without renewing the marriage contract. Your statement, "I have taken my wife back," is sufficient, and having witnesses to the reconciliation is recommended.