italki – Which is correct, in the meeting or at the meeting Hello, friends. Please tell me which is a right e

Which to use depends on the context. The others appear to have interpreted your question to refer to people being in the meeting, which is correct.
Given what you said about emails, I assumed you are referring to things that happened at the meeting. In that case, at is usually the correct option.
I’m sure that you tabled your schedule at the meeting. We discussed that at the meeting. You were present at the meeting.
But, if you are referring to ‘presence’ – then you use ‘in’. Your secretary rang while you were in the meeting.
If you can give an example, we can look at it and see if it is correct, and perhaps explain why.