Indefinite leave to remain in the UK is known as ‘settlement’ or ‘ILR’ which means you can stay in the UK without any time restrictions. If you are granted ILR you are free to enter and work in the UK without any restrictions, so long as you abide by the UK laws.

You must usually complete a qualifying period prior to applying for settlement in the UK and can be applied for through a number of routes. 

House with Pool
House with Pool

SETTLEMENT (ILR)