Studying in China usually means an X visa, of two types: X1 (study over 180 days; must convert to a residence permit after entry) and X2 (study up to 180 days; stay directly).
Process: 1) receive the admission letter plus the JW201 (government scholarship) or JW202 (self-funded) visa application form; 2) apply for the X visa at a Chinese embassy or consulate with passport, photos, admission letter and JW form.
X1 holders must apply for a "foreigner residence permit" (study) at the local exit-entry administration within 30 days of arrival - this permit enables long-term stay and multiple entries.
Renewal: permits usually match the academic year (half-year to one year); renew within 30 days before expiry with proof of enrolment, passport and photos.
Common questions: minors under 18 need guardian documents; changing schools requires a permit change; travelling home during holidays is fine while the permit is valid.
After graduation: you can apply for a 1-2 year job-seeking visa to look for work, or convert directly to a work permit.