Hello, my husband and I will be moving to Shanghai for work (he has the job)

and I would like to invite my sister to stay with us for an extended amount of time. What is the maximum stay we can apply for her?

Should we apply for a tourist visa first and then apply for the S2 for her one she is in Shanghai? also, I read above the S2 type must remain in China; what does this mean? we will want to travel out for fun and return within that time of stay.

Thank you for your help