Which sounds more natural to native speakers between "my name is..." and "I'm ..."?
They are both acceptable as simple introductions! There is no more "natural" expression, but "I'm [name]" is a bit more casual due to its simplicity and conciseness. Make sure that you use an expression appropriate for the occasion (i.e. formal or professional vs. casual or informal). Ex: Hello, my name is Stephanie. It's great to meet you all. (More formal) Ex: Hey guys, what's up? (Casual) Ex: Hi everyone, I'm Stephanie. Happy to be here. (Professional)