For example, if I were to take an online course or a class at a community college, would admissions officers see the grades I earned in these classes and factor them into my cumulative GPA?
Yes.
Per AMCAS and ACOMAS rules, any coursework that generates a college transcript is included when calculating your GPA and sGPA when applying to medical school. This includes any courses taken during high school as co-enrollment or for enrichment.
You are required to report the grades from and provide a transcript for all colleges you have ever attended, including community colleges and online colleges.
Thank you so much for the helpful information!