Electrophilic additions are also referred to as addition reactions.
| An additionCH2=CH2 + HX → CH3-CH2X | 
| Its reverse, an eliminationCH3-CH2X + base, Δ → CH2=CH2 | 
Electrophilic additions are essentially the reverse of an E1 elimination reaction, sometimes exactly the microscopic reverse.
| Microscopic reverseThis means that the mechanism of the reaction follows each and every step of the related reaction in reverse order, without deviation. Sometimes, a reaction can be reversed but using a different series of tiny steps. When that happens, it is NOT called a microscopic reverse. | 
Addition reactions involve carbocations. This intermediate carbocation can rearrange.
Addition reactions follow Markovnikov's rule. (The higher priority substituent adds to the more highly substituted carbon of the carbon-carbon double bond).
(Series of sample reactions here)