Significant figures are the digits in a measurement that are known with certain plus one digit that is estimated. Recognizing the number of significant figures in a measured quantity is easy for measurements that someone personally makes

Scientists use significant figures to clearly express the precision of measurements. The number of significant figures used to express the measurement is determined by the number of figures that are certain in measurement plus one additional figure that expresses uncertainty.
The following are the steps involved in finding the significant figures.
Step-1: Note down the given values in the problem.
Step-2: All digits other than zero are significant. Zeros between nonzero digit are significant. Final zeros to the right of the decimal point are significant. 
Step-3: In numbers smaller than 1, zeros to the left or directly to the right of the decimal point are not significant.