How could I know someone logined to trello board?

Questions
1

Hi,

Is there any trello trigger help me know someone (with email) logined to trello board?

2

Not sure what you mean with “logined to trello board”. That they got added to the board? If so that exists. You can find a list of all the available events here:
https://developer.atlassian.com/cloud/trello/guides/rest-api/action-types/