Was there a difference between atomic bombs and if so, what is the difference?

Answer

Are you talking about the bombs on Hirochima and Nagasaki in your question?
I can’t say for sure from your question, but I’m assuming it is.

There were indeed differences between these two bombs.
The Hiroshima bomb (the “Little Boy”) was based on U-235, and the detonator that brought the two subcritical masses together was linear. One subcritical mass was brought to another from a straight line.
The bomb on Nagasaki (the “Fat Man”) was a spherical construction with a plutonium core. The critical mass was reached here by the implosion of a uranium mantle surrounding the plutonium core.

If you browse the keywords “little boy fat man” you will find numerous websites with the specifications of both bombs, more specifically how the explosion was brought about.