The basic process is to charge at constant current until each cell reaches 4.2V.
The charger then switches to a constant voltage mode, and the charging current will gradually reduce while the charger holds the cell voltage at 4.2V. This will continue until the charge current has dropped to a small percentage of the initial charge rate, at which point the battery is considered fully charged. Some manufacturers specify 2%, others 3%, but other values are also possible. The difference in achieved capacity is minute.