Do you have to shake hands to take bay’ah?

Spoken words are enough to take bay'ah (also written bai'at, bay'at, baiat or bayt), because bay'ah is a pledge. However, it is a Sunnah for men to offer their hands when taking bay'ah with their shaykh.

Holding the hands of women while taking bay'ah, the practice of certain ignorant and imprudent men, is completely unacceptable in the Shariah, as it is prohibited to touch an unrelated woman.

The practice of the Beloved Prophet ﷺ is narrated by Sayyidah Ayesha may Allah be pleased with her: "Never once in his life did Allah's Messenger ﷺ touch the hand of a woman who was not related to him. He took Bayá from them verbally. And when a woman pledged, he would then say to her, 'Go, I have accepted your pledge.'" [Sahih al-Bukhari 2713] No one is more chaste than the Beloved Prophet ﷺ and he was extremely cautious, therefore one must follow in his footsteps.