How can a Christian maid who wishes to convert to Islam be helped while she is in a foreign country, and what is the correct step to declare her conversion to Islam given the unavailability of a trustworthy shaykh?

The Christian maid must immediately pronounce the Two Testimonies (Shahadatayn) to become a Muslim. It is not a condition to declare this before a scholar or in court. Once she pronounces the Two Testimonies and believes in their meaning, she becomes a Muslim, having the same rights and obligations as other Muslims. You must teach her the prayer (Salah), its conditions, and the rest of the pillars of Islam and obedience to Allah. When you return to your country, register her conversion to Islam at the Sharia court to change her official documents so that she can marry a Muslim and perform other transactions that require proof of religion. You will be rewarded for inviting her to Islam, and you will receive a reward similar to what she will perform in acts of worship.