Check whether you need any visa to enter in to Spain. If your country is under the list of countries that do not require a Spain visa to enter, you are not required to apply for visa. The above link has the details of visa free travel to Spain list
There are some types of Spain visa such as Spain short stay visa, Spain long stay visa, Spain work visa, Spain business visa, Spain student visa and Spain residence visa. Check the above link for the process of visa and more details of each type of visas.
You need to pay for each type of Spain visa. Check the above link for Spain visa fee details.