What is the difference between char and varchar data types?

Set char to occupy n bytes and it will take n bytes even if we are
storing a value of n-m bytes

Set varchar to occupy n bytes and it will take only the required space
and will not use the n bytes

Eg: name char(15) will waste 10 bytes if we store ‘mizan’, if each char
takes a byte
Eg: name varchar(15) will just use 5 bytes if we store ‘mizan’, if each
char takes a byte. rest 10 bytes will be free.