Questions regarding mol files
For bond block the numbering can be done at random or it has to follow some order


Bonds don't need to be in any particular order, although usually bonds are created first for atom 1, then atom 2, etc. However, the first bond could be between atom 101 and atom 100 if you wish.


  Also in the atom block the order in which atoms occur can it be random or again it has to follow any order


Atoms can be in any order. Some programs use "canonical ordering" so that the same molecule will always have the same atomic order, but this is rarely used because it can be time-consuming.


  Is order of numbering done in bond block and atom block related


As indicated above, both the atom and bond blocks could be in random order. The relation, obviously, is that for a given molecular structure, there will be bonds between bonded atom pairs.


  Is there any free software which converts mol files to structure


There are many, but you don't describe whether you want 3D (presumably) or 2D structures.

Personally, I suggest Avogadro which can create 3D coordinates for files.

If you're generating a large batch of 3D structures, you will likely want to use Open Babel or RDKit or something similar. Both are open source and free.