Inform, acquaint, apprise, advise, notify are comparable when meaning to make (one) aware or cognizant of something.
One informs a person of something when one imparts knowledge, particularly of occurrences or of facts necessary to the understanding of a situation. Also, one informs oneself when by study or investigation one gathers the pertinent facts. Inform in one specific use also carries the implication of talebearing or accusation.
One acquaints a person with something when by introducing him to the experience of it or by imparting information concerning it one makes him familiar with it. Familiarity is even more strongly implied in the participial adjective acquainted.
One apprises a person of something when by a message or sign one communicates it to him.
One advises a person of something when one gives him information about it, especially of a kind that is important to him (as in making a decision, determining a policy, or arranging plans). Often there is a suggestion of forewarning or counsel (see also advise under ADVICE 1 ).
One notifies a person of something when one sends a notice or formal communication concerning it, usually as a matter requiring his attention. In commercial use, advise is used in preference to notify when information is given by letter, telegram, or cable.