Two events. De-ice is on the ground before flt. Usually some type of heated fluid. This is a fairly good summary moving from fluids to the goop. There are 'hold-over' charts that give you times from application to loss of protection.

Anti-ice comes in various forms from bleed air off the engines to heated surfaces. Failing that, ice will sublimate at the higher speeds. For example, in the 727we didn't worry too much about acreting ice on climbout or descent as we were well above 300kts. The problem was picking up the stuff in the pattern. Worst was picking up a big load on the tail and losing effectiveness.