Fashion advice on ladies office wear ?

I need some fashion advice on ladies office wear . There are a few questions. What kind of dresses can be worn under a blazer ? What is the difference between a vest and camisole ? Can both be worn under a blazer ? Do the blazer always need to be oned at office ? What are the etiquette regarding blazer? Can I wear short sleeved or 3/4th sleeved collar shirts under a blazer ? Is it improper if the end of the sleeve of shirt worn beneath the blazer peeps out at the wrist ? or is it a fashion that it must be shown out ? please advice.