I’ve not come across ManyChat, a service to build chat bots on Facebook Messenger, but they have free account options. In this demonstration by Gilbert Mizrahi (@GilbertMizrahi) you can learn how ManyChat can be used with Apps Script to update data in a Google Sheet row.
Source: How to edit a row in Google Sheets via ManyChat using Apps Script – Baloka
Member of Google Developers Experts Program for Google Workspace (Google Apps Script) and interested in supporting Google Workspace Devs.