The term Sampling means selecting a sample from a population. There are multiple ways of doing it. Some of the techniques are purely based on probability and some of them are non-probability based. According to the requirement, we choose a sampling type and collect data. There is a no-one-fit answer to every problem, you need to look at your problem statement and you need to decide which sampling technique is best suitable.
Sampling techniques falling under this category ensure that the sample taken is random. These techniques help in taking bias-free samples, but these techniques are harder to conduct.
Non-Probability Based Sampling:
Sampling techniques falling under this category do not follow probability theory means the chance of being selected may or may not be equal. One item may have a greater chance of being selected over another. These techniques are simpler to conduct, but this may result in a biased sample and the conclusions will not be truly trustworthy.