First of all, take a deep breath and use some punctuation; periods and commas are your friends. We can better answer your questions when they're easy to read.
Anyway, I am not a lawyer and this is not legal advice (yadda yadda yadda), but this is the legal situation to the best of my knowledge:
You can carry any length or type of knife (except switchblades) OPENLY in Michigan. The issue of concealment is unfortunately vague in Michigan, although that may be fixed by bill HB4262 currently in the Michigan Senate. You cannot carry a "dangerous weapon" concealed on or about your person, and knives with blades longer 3" are sometimes thought of as dangerous weapons. However, they are never explicitly defined as dangerous weapons in Michigan law, and at least one legal case supports this.* That said, it's probably best to be safe and not to conceal a fixed blade longer than 3" ("except a hunting knife adapted and carried as such"). You may be fine carrying a larger folder in your pocket, though I can't recommend that you risk it. A folder clipped to the top of your pocket may not even be considered concealed, however, if it isn't covered by your shirt/coat - although that determination would ultimately be up to the arresting police officer.
Here's the law (and check the concealment-related legal cases at the bottom): http://knife-expert.com/mi.txt
*- The case I mentioned, althought it's old:
"An ordinary jackknife with a pointed blade 3-5/16 inches
long was not a 'dangerous weapon...' in the absence of
evidence that it was used or carried for use as a weapon."