There is a difference between mold and mould but only in spelling, the meaning is the same. The mold is commonly used in American English and meaning is to form the material as mold and the fungi which are developed on fungi. The Mould is British spelling and they don’t use the mold. The mold and mould have the same meaning with a different spelling.
So When using the mold?
The mold can be used as a noun or a verb.
Sometimes mold as a noun meaning fungus that grows on organic matter. Look at this sentence.
I want to eat bread which I made a week ago but it had mold on it.
Mold is also used in a process where liquid turns into solid. Look at these sentences.
The molten plastic poured into mould to get proper shape and size.
The new mold is required for the new design.
Sometimes it is used as a verb as transforming from.
We can mold everything as per your need.
Now, what is the meaning of Mould?
The Mould is mostly used in British English. It is used the same as mold in British English. The difference is only in spelling but the meaning is the same at both places.
In the end, what are mold and mould? Both are the same but use at a different place.