What's the difference between an admission notice and a formal admission notice?

There is no difference between the admission notice of the preparatory class and the formal admission notice. It's just that recruits are different

Ordinary institutions of higher learning or ethnic colleges designated by the state shall select preparatory students on a voluntary basis from candidates who meet certain conditions in the national college entrance examination that year and score less than a certain score. It is the need of the party and the country to improve the cultural level of ethnic minorities. Special measures taken to speed up the development of socialist modernization in ethnic minority areas and remote areas and train more ethnic minority professionals.

The admission notice is sent directly to the candidates by the admissions school. Candidates who have been admitted to the preparatory class report to the preparatory training school with the admission notice of the preparatory class. Preparatory training schools should send relevant materials such as freshmen's admission instructions to relevant enrollment schools in advance.

Extended data:

Preparatory classes and colleges and universities volunteer to fill in at the same time, preparatory classes volunteer to fill in the corresponding batch of colleges and universities preparatory classes volunteer column. Candidates who apply for the first batch of undergraduate matriculation courses in colleges and universities fill in the column of "Volunteer for the first batch of undergraduate matriculation courses"; Candidates who apply for the second batch of undergraduate preparatory courses in undergraduate colleges should fill in the column of "the second batch of undergraduate preparatory courses".

Candidates applying for the second batch of undergraduate and junior college preparatory courses should fill in the column of "Volunteer for Junior College and Junior College Preparatory Course".