I need some information about forced and arranged marriages in Afghanistan. I also need information about child marriage.
Not sure what kind of information you are looking for, but I can give you a general overview of the issue.
Afghanistan isn't really a country. It's a collection of tribes that happen to have a border around them. The population is largely uneducated, rural, and lives very traditional and usually religious lives, following a stricter brand of Islam than in most countries.
As in Pakistan also, arranged marriages are common. Often a person will know who they are going to marry from a very young age. Marriage is not as often for love as it is for a father to find a way for his daughter to survive, or to unite tribes and families together. There is not often resistance from women or young girls to this practice, as it just wouldn't be tolerated.
As most of the population lives in villages and small towns, the age of consent we are familiar with in the US does not apply. People get married much younger, in part because they don't live as long. Life expectancy in Afghanistan is in the 40's for both men and women.