The Logarithm is the inverse function to exponentiation. This means that if we have a number x , we need to find x is the exponent to which another fixed number, the base b, must be raised, to produce that number x.

Also Logarithm is a tool to smoothen the boundary of a curve and to approximate a large set of values in a small region of space.

You can consider the khan academy materials available online for free, in order to understand logarithm in a practical way.

I hope this helps. Wish you a great day!